24 game
You are encouraged to solve this task according to the task description, using any language you may know.
The 24 Game tests one's mental arithmetic.
- Task
Write a program that randomly chooses and displays four digits, each from 1 ──► 9 (inclusive) with repetitions allowed.
The program should prompt for the player to enter an arithmetic expression using just those, and all of those four digits, used exactly once each. The program should check then evaluate the expression.
The goal is for the player to enter an expression that (numerically) evaluates to 24.
- Only the following operators/functions are allowed: multiplication, division, addition, subtraction
- Division should use floating point or rational arithmetic, etc, to preserve remainders.
- Brackets are allowed, if using an infix expression evaluator.
- Forming multiple digit numbers from the supplied digits is disallowed. (So an answer of 12+12 when given 1, 2, 2, and 1 is wrong).
- The order of the digits when given does not have to be preserved.
- Notes
- The type of expression evaluator used is not mandated. An RPN evaluator is equally acceptable for example.
- The task is not for the program to generate the expression, or test whether an expression is even possible.
- Related tasks
- Reference
- The 24 Game on h2g2.
8th
This is a fully-worked sample of the game in 8th, showing error-detection and user-restriction techniques: <lang forth> \ Generate four random digits and display to the user \ then get an expression from the user using +, -, / and * and the digits \ the result must equal 24 \ http://8th-dev.com/24game.html
\ Only the words in namespace 'game' are available to the player: ns: game
- + n:+ ;
- - n:- ;
- * n:* ;
- / n:/ ;
ns: G
var random-digits var user-input
- one-digit \ a -- a
rand n:abs 9 n:mod n:1+ a:push ;
- gen-digits \ - a
[] clone nip \ the clone nip is not needed in versions past 1.0.2... ' one-digit 4 times ' n:cmp a:sort random-digits ! ;
- prompt-user
cr "The digits are: " . random-digits @ . cr ;
- goodbye
cr "Thanks for playing!\n" . cr 0 die ;
- get-input
70 null con:accept dup user-input ! null? if drop goodbye then ;
- compare-digits
true swap ( \ inputed-array index dup >r a:@ random-digits @ r> a:@ nip n:= not if break swap drop false swap then ) 0 3 loop drop ;
/^\D*(\d)\D+(\d)\D+(\d)\D+(\d)\D*$/ var, digits-regex
- all-digits?
user-input @ digits-regex @ r:match null? if drop false else 5 = not if false else \ convert the captured digits in the regex into a sorted array: digits-regex @ ( r:@ >n swap ) 1 4 loop drop 4 a:close ' n:cmp a:sort compare-digits then then ;
- does-eval?
0 user-input @ eval 24 n:= dup not if cr "Sorry, that expression is wrong" . cr then ;
- check-input
reset all-digits? if does-eval? if cr "Excellent! Your expression: \"" . user-input @ . "\" worked!" . cr then else cr "You did not use the digits properly, try again." . cr then ;
- intro quote |
Welcome to the '24 game'!
You will be shown four digits each time. Using only the + - * and / operators and all the digits (and only the digits), produce the number '24'
Enter your result in 8th syntax, e.g.: 4 4 + 2 1 + *
To quit the game, just hit enter by itself. Enjoy!
| . ;
- start
\ don't allow anything but the desired words ns:game only intro repeat gen-digits prompt-user get-input check-input again ;
start </lang>
AArch64 Assembly
<lang AArch64 Assembly> /* ARM assembly AARCH64 Raspberry PI 3B */ /* program game24_64.s */
/*******************************************/ /* Constantes file */ /*******************************************/ /* for this file see task include a file in language AArch64 assembly*/ .include "../includeConstantesARM64.inc"
.equ NBDIGITS, 4 // digits number .equ TOTAL, 24 .equ BUFFERSIZE, 100 .equ STACKSIZE, 10 // operator and digits number items in stacks
/*********************************/
/* Initialized data */
/*********************************/
.data
szMessRules: .ascii "24 Game 64 bits.\n"
.ascii "The program will display four randomly-generated \n" .ascii "single-digit numbers and will then prompt you to enter\n" .ascii "an arithmetic expression followed by <enter> to sum \n" .ascii "the given numbers to 24.\n" .asciz "Exemple : 9+8+3+4 or (7+5)+(3*4) \n\n"
szMessExpr: .asciz "Enter your expression (or type (q)uit to exit or (n) for other digits): \n" szMessDigits: .asciz "The four digits are @ @ @ @ and the score is 24. \n" szMessNoDigit: .asciz "Error : One digit is not in digits list !! \n" szMessSameDigit: .asciz "Error : Two digits are same !! \n" szMessOK: .asciz "It is OK. \n" szMessNotOK: .asciz "Error, it is not ok total = @ \n" szMessErrOper: .asciz "Unknow Operator (+,-,$,/,(,)) \n" szMessNoparen: .asciz "no opening parenthesis !! \n" szMessErrParen: .asciz "Error parenthesis number !! \n" szMessNoalldigits: .asciz "One or more digits not used !!\n" szMessNewGame: .asciz "New game (y/n) ? \n" szCarriageReturn: .asciz "\n" .align 4 qGraine: .quad 123456 /*********************************/ /* UnInitialized data */ /*********************************/ .bss sZoneConv: .skip 24 sBuffer: .skip BUFFERSIZE iTabDigit: .skip 8 * NBDIGITS iTabTopDigit: .skip 8 * NBDIGITS /*********************************/ /* code section */ /*********************************/ .text .global main main: // entry of program
ldr x0,qAdrszMessRules // display rules bl affichageMess
1:
mov x3,#0 ldr x12,qAdriTabDigit ldr x11,qAdriTabTopDigit ldr x5,qAdrszMessDigits
2: // loop generate random digits
mov x0,#8 bl genereraleas add x0,x0,#1 str x0,[x12,x3,lsl #3] // store in table mov x1,#0 str x1,[x11,x3,lsl #3] // raz top table ldr x1,qAdrsZoneConv bl conversion10 // call decimal conversion //mov x2,#0 //strb w2,[x1,x0] // reduce size display area with zéro final mov x0,x5 ldr x1,qAdrsZoneConv // insert conversion in message bl strInsertAtCharInc mov x5,x0 add x3,x3,#1 cmp x3,#NBDIGITS // end ? blt 2b // no -> loop mov x0,x5 bl affichageMess
3: // loop human entry
ldr x0,qAdrszMessExpr bl affichageMess bl saisie // entry cmp x0,#'q' beq 100f cmp x0,#'Q' beq 100f cmp x0,#'n' beq 1b cmp x0,#'N' beq 1b bl evalExpr // expression evaluation cmp x0,#0 // ok ? bne 3b // no - > loop
10: // display new game ?
ldr x0,qAdrszCarriageReturn bl affichageMess ldr x0,qAdrszMessNewGame bl affichageMess bl saisie cmp x0,#'y' beq 1b cmp x0,#'Y' beq 1b
100: // standard end of the program
mov x0, #0 // return code mov x8, #EXIT // request to exit program svc #0 // perform the system call
qAdrszCarriageReturn: .quad szCarriageReturn qAdrszMessRules: .quad szMessRules qAdrszMessDigits: .quad szMessDigits qAdrszMessExpr: .quad szMessExpr qAdrszMessNewGame: .quad szMessNewGame qAdrsZoneConv: .quad sZoneConv qAdriTabDigit: .quad iTabDigit qAdriTabTopDigit: .quad iTabTopDigit /******************************************************************/ /* evaluation expression */ /******************************************************************/ /* x0 return 0 if ok -1 else */ evalExpr:
stp x1,lr,[sp,-16]! // save registres stp x2,x3,[sp,-16]! // save registres stp x4,x5,[sp,-16]! // save registres stp x6,x7,[sp,-16]! // save registres stp x8,x9,[sp,-16]! // save registres stp x10,fp,[sp,-16]! // save registres mov x0,#0 ldr x1,qAdriTabTopDigit mov x2,#0
1: // loop init table top digits
str x0,[x1,x2,lsl #3] add x2,x2,#1 cmp x2,#NBDIGITS blt 1b sub sp,sp,#STACKSIZE * 8 // stack operator mov fp,sp sub sp,sp,#STACKSIZE * 8 // stack digit mov x1,sp ldr x10,qAdrsBuffer mov x8,#0 // indice character in buffer mov x7,#0 // indice digits stack mov x2,#0 // indice operator stack mov x9,0
1: // begin loop
ldrb w9,[x10,x8] cmp x9,#0xA // end expression ? beq 90f cmp x9,#' ' // space ? cinc x8,x8,eq // loop beq 1b cmp x9,#'(' // left parenthesis -> store in operator stack bne 11f str x9,[fp,x2,lsl 3] add x2,x2,#1 add x8,x8,#1 // and loop b 1b
11:
cmp x9,#')' // right parenthesis ? bne 3f mov x0,fp // compute operator stack until left parenthesis sub x2,x2,#1
2:
ldr x6,[fp,x2,lsl 3] cmp x6,#'(' // left parenthesis cinc x8,x8,eq // end ? beq 1b // and loop sub x7,x7,#1 // last digit mov x3,x7 bl compute sub x2,x2,#1 cmp x2,#0 bge 2b ldr x0,qAdrszMessNoparen // no left parenthesis in stack bl affichageMess mov x0,#-1 b 100f
3:
cmp x9,#'+' // addition beq 4f cmp x9,#'-' // soustraction beq 4f cmp x9,#'*' // multiplication beq 4f cmp x9,#'/' // division beq 4f
b 5f // not operator
4: // control priority and depile stacks
mov x0,fp mov x3,x7 mov x4,x9 bl depileOper mov x7,x3 add x8,x8,#1 b 1b // and loop
5: // digit
sub x9,x9,#0x30 mov x0,x9 bl digitControl cmp x0,#0 // error ? bne 100f str x9,[x1,x7,lsl #3] // store digit in digits stack add x7,x7,#1
add x8,x8,#1 beq 1b
b 100f
90: // compute all stack operators
mov x0,fp sub x7,x7,#1
91:
subs x2,x2,#1 blt 92f mov x3,x7 bl compute sub x7,x7,#1 b 91b
92:
ldr x0,[x1] // total = first value on digits stack cmp x0,#TOTAL // control total beq 93f // ok ldr x1,qAdrsZoneConv bl conversion10 // call decimal conversion mov x2,#0 strb w2,[x1,x0] ldr x0,qAdrszMessNotOK ldr x1,qAdrsZoneConv // insert conversion in message bl strInsertAtCharInc bl affichageMess mov x0,#-1 b 100f
93: // control use all digits
ldr x1,qAdriTabTopDigit mov x2,#0
94: // begin loop
ldr x0,[x1,x2,lsl #3] // load top cmp x0,#0 bne 95f ldr x0,qAdrszMessNoalldigits bl affichageMess mov x0,#-1 b 100f
95:
add x2,x2,#1 cmp x2,#NBDIGITS blt 94b
96: // display message OK
ldr x0,qAdrszMessOK bl affichageMess mov x0,#0 b 100f
100:
add sp,sp,8 * (STACKSIZE *2) // stack algnement ldp x10,fp,[sp],16 // restaur des 2 registres ldp x8,x9,[sp],16 // restaur des 2 registres ldp x6,x7,[sp],16 // restaur des 2 registres ldp x4,x5,[sp],16 // restaur des 2 registres ldp x2,x3,[sp],16 // restaur des 2 registres ldp x1,lr,[sp],16 // restaur des 2 registres ret
qAdrszMessNoparen: .quad szMessNoparen qAdrszMessNotOK: .quad szMessNotOK qAdrszMessOK: .quad szMessOK qAdrszMessNoalldigits: .quad szMessNoalldigits /******************************************************************/ /* depile operator */ /******************************************************************/ /* x0 operator stack address */ /* x1 digits stack address */ /* x2 operator indice */ /* x3 digits indice */ /* x4 operator */ /* x2 return a new operator indice */ /* x3 return a new digits indice */ depileOper:
stp x4,lr,[sp,-16]! // save registres stp x5,x6,[sp,-16]! // save registres stp x7,x8,[sp,-16]! // save registres cmp x2,#0 // first operator ? beq 60f sub x5,x2,#1
1:
ldr x6,[x0,x5,lsl #3] // load stack operator cmp x6,x4 // same operators beq 50f cmp x6,#'*' // multiplication beq 50f cmp x6,#'/' // division beq 50f cmp x6,#'-' // soustraction beq 50f b 60f
50: // depile operators stack and compute
sub x2,x2,#1 sub x3,x3,#1 bl compute sub x5,x5,#1 cmp x5,#0 bge 1b
60:
str x4,[x0,x2,lsl #3] // add operator in stack add x2,x2,#1
100:
ldp x7,x8,[sp],16 // restaur des 2 registres ldp x5,x6,[sp],16 // restaur des 2 registres ldp x4,lr,[sp],16 // restaur des 2 registres ret
/******************************************************************/ /* compute */ /******************************************************************/ /* x0 operator stack address */ /* x1 digits stack address */ /* x2 operator indice */ /* x3 digits indice */ compute:
stp x1,lr,[sp,-16]! // save registres stp x2,x3,[sp,-16]! // save registres stp x4,x5,[sp,-16]! // save registres stp x6,x7,[sp,-16]! // save registres stp x8,x9,[sp,-16]! // save registres ldr x6,[x1,x3,lsl 3] // load second digit sub x5,x3,#1 ldr x7,[x1,x5,lsl 3] // load first digit ldr x8,[x0,x2,lsl 3] // load operator cmp x8,#'+' bne 1f add x7,x7,x6 // addition str x7,[x1,x5,lsl 3] b 100f
1:
cmp x8,#'-' bne 2f sub x7,x7,x6 // soustaction str x7,[x1,x5,lsl 3] b 100f
2:
cmp x8,#'*' bne 3f // multiplication mul x7,x6,x7 str x7,[x1,x5,lsl 3] b 100f
3:
cmp x8,#'/' bne 4f udiv x7,x7,x6 // division str x7,[x1,x5,lsl 3] b 100f
4:
cmp x8,#'(' // left parenthesis ? bne 5f ldr x0,qAdrszMessErrParen // error bl affichageMess mov x0,#-1 b 100f
5:
ldr x0,qAdrszMessErrOper bl affichageMess mov x0,#-1
100:
ldp x8,x9,[sp],16 // restaur des 2 registres ldp x6,x7,[sp],16 // restaur des 2 registres ldp x4,x5,[sp],16 // restaur des 2 registres ldp x2,x3,[sp],16 // restaur des 2 registres ldp x1,lr,[sp],16 // restaur des 2 registres ret
qAdrszMessErrOper: .quad szMessErrOper qAdrszMessErrParen: .quad szMessErrParen /******************************************************************/ /* control digits */ /******************************************************************/ /* x0 return 0 if OK 1 if not digit */ digitControl:
stp x1,lr,[sp,-16]! // save registres stp x2,x3,[sp,-16]! // save registres stp x4,x5,[sp,-16]! // save registres ldr x1,qAdriTabTopDigit ldr x2,qAdriTabDigit mov x3,#0
1:
ldr x4,[x2,x3,lsl #3] // load digit cmp x0,x4 // equal ? beq 2f // yes add x3,x3,#1 // no -> loop cmp x3,#NBDIGITS // end ? blt 1b ldr x0,qAdrszMessNoDigit // error bl affichageMess mov x0,#1 b 100f
2: // control prev use
ldr x4,[x1,x3,lsl #3] cmp x4,#0 beq 3f add x3,x3,#1 cmp x3,#NBDIGITS blt 1b ldr x0,qAdrszMessSameDigit bl affichageMess mov x0,#1 b 100f
3:
mov x4,#1 str x4,[x1,x3,lsl #3] mov x0,#0
100:
ldp x4,x5,[sp],16 // restaur des 2 registres ldp x2,x3,[sp],16 // restaur des 2 registres ldp x1,lr,[sp],16 // restaur des 2 registres ret
qAdrszMessNoDigit: .quad szMessNoDigit qAdrszMessSameDigit: .quad szMessSameDigit /******************************************************************/ /* string entry */ /******************************************************************/ /* x0 return the first character of human entry */ saisie:
stp x1,lr,[sp,-16]! // save registres stp x2,x3,[sp,-16]! // save registres stp x4,x5,[sp,-16]! // save registres stp x6,x7,[sp,-16]! // save registres mov x0,STDIN // Linux input console ldr x1,qAdrsBuffer // buffer address mov x2,BUFFERSIZE // buffer size mov x8,READ // request to read datas svc 0 // call system ldr x1,qAdrsBuffer // buffer address ldrb w0,[x1] // load first character
100:
ldp x6,x7,[sp],16 // restaur des 2 registres ldp x4,x5,[sp],16 // restaur des 2 registres ldp x2,x3,[sp],16 // restaur des 2 registres ldp x1,lr,[sp],16 // restaur des 2 registres ret
qAdrsBuffer: .quad sBuffer /***************************************************/ /* Generation random number */ /***************************************************/ /* x0 contains limit */ genereraleas:
stp x1,lr,[sp,-16]! // save registres stp x2,x3,[sp,-16]! // save registres stp x4,x5,[sp,-16]! // save registres ldr x4,qAdrqGraine ldr x2,[x4] ldr x3,qNbDep1 mul x2,x3,x2 ldr x3,qNbDep2 add x2,x2,x3 str x2,[x4] // maj de la graine pour l appel suivant cmp x0,#0 beq 100f add x0,x0,#1 udiv x3,x2,x0 msub x0,x3,x0,x2 // résult = remainder ldp x4,x5,[sp],16 // restaur des 2 registres ldp x2,x3,[sp],16 // restaur des 2 registres ldp x1,lr,[sp],16 // restaur des 2 registres ret
/*****************************************************/ qAdrqGraine: .quad qGraine qNbDep1: .quad 0x0019660d qNbDep2: .quad 0x3c6ef35f /********************************************************/ /* File Include fonctions */ /********************************************************/ /* for this file see task include a file in language AArch64 assembly */ .include "../includeARM64.inc" </lang>
ABAP
See 24 game/ABAP
Ada
game24.adb: <lang Ada>with Ada.Float_Text_IO; with Ada.Text_IO; with Ada.Numerics.Discrete_Random; procedure Game_24 is
subtype Digit is Character range '1' .. '9'; package Random_Digit is new Ada.Numerics.Discrete_Random (Digit); Exp_Error : exception; Digit_Generator : Random_Digit.Generator; Given_Digits : array (1 .. 4) of Digit; Float_Value : constant array (Digit) of Float := (1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0); function Apply_Op (L, R : Float; Op : Character) return Float is begin case Op is when '+' => return L + R; when '-' => return L - R; when '*' => return L * R; when '/' => return L / R; when others => Ada.Text_IO.Put_Line ("Unexpected operator: " & Op); raise Exp_Error; end case; end Apply_Op; function Eval_Exp (E : String) return Float is Flt : Float; First : Positive := E'First; Last : Positive; function Match_Paren (Start : Positive) return Positive is Pos : Positive := Start + 1; Level : Natural := 1; begin loop if Pos > E'Last then Ada.Text_IO.Put_Line ("Unclosed parentheses."); raise Exp_Error; elsif E (Pos) = '(' then Level := Level + 1; elsif E (Pos) = ')' then Level := Level - 1; exit when Level = 0; end if; Pos := Pos + 1; end loop; return Pos; end Match_Paren; begin if E (First) = '(' then Last := Match_Paren (First); Flt := Eval_Exp (E (First + 1 .. Last - 1)); elsif E (First) in Digit then Last := First; Flt := Float_Value (E (First)); else Ada.Text_IO.Put_Line ("Unexpected character: " & E (First)); raise Exp_Error; end if; loop if Last = E'Last then return Flt; elsif Last = E'Last - 1 then Ada.Text_IO.Put_Line ("Unexpected end of expression."); raise Exp_Error; end if; First := Last + 2; if E (First) = '(' then Last := Match_Paren (First); Flt := Apply_Op (Flt, Eval_Exp (E (First + 1 .. Last - 1)), Op => E (First - 1)); elsif E (First) in Digit then Last := First; Flt := Apply_Op (Flt, Float_Value (E (First)), Op => E (First - 1)); else Ada.Text_IO.Put_Line ("Unexpected character: " & E (First)); raise Exp_Error; end if; end loop; end Eval_Exp;
begin
Ada.Text_IO.Put_Line ("24 Game"); Ada.Text_IO.Put_Line ("- Enter Q to Quit"); Ada.Text_IO.Put_Line ("- Enter N for New digits"); Ada.Text_IO.Put_Line ("Note: Operators are evaluated left-to-right"); Ada.Text_IO.Put_Line (" (use parentheses to override)"); Random_Digit.Reset (Digit_Generator); <<GEN_DIGITS>> Ada.Text_IO.Put_Line ("Generating 4 digits..."); for I in Given_Digits'Range loop Given_Digits (I) := Random_Digit.Random (Digit_Generator); end loop; <<GET_EXP>> Ada.Text_IO.Put ("Your Digits:"); for I in Given_Digits'Range loop Ada.Text_IO.Put (" " & Given_Digits (I)); end loop; Ada.Text_IO.New_Line; Ada.Text_IO.Put ("Enter your Expression: "); declare Value : Float; Response : constant String := Ada.Text_IO.Get_Line; Prev_Ch : Character := ' '; Unused_Digits : array (Given_Digits'Range) of Boolean := (others => True); begin if Response = "n" or Response = "N" then goto GEN_DIGITS; end if; if Response = "q" or Response = "Q" then return; end if; -- check input for I in Response'Range loop declare Ch : constant Character := Response (I); Found : Boolean; begin if Ch in Digit then if Prev_Ch in Digit then Ada.Text_IO.Put_Line ("Illegal multi-digit number used."); goto GET_EXP; end if; Found := False; for J in Given_Digits'Range loop if Unused_Digits (J) and then Given_Digits (J) = Ch then Unused_Digits (J) := False; Found := True; exit; end if; end loop; if not Found then Ada.Text_IO.Put_Line ("Illegal number used: " & Ch); goto GET_EXP; end if; elsif Ch /= '(' and Ch /= ')' and Ch /= '+' and Ch /= '-' and Ch /= '*' and Ch /= '/' then Ada.Text_IO.Put_Line ("Illegal character used: " & Ch); goto GET_EXP; end if; Prev_Ch := Ch; end; end loop; -- check all digits used for I in Given_Digits'Range loop if Unused_Digits (I) then Ada.Text_IO.Put_Line ("Digit not used: " & Given_Digits (I)); goto GET_EXP; end if; end loop; -- check value begin Value := Eval_Exp (Response); exception when Exp_Error => goto GET_EXP; -- Message displayed by Eval_Exp; end; if abs (Value - 24.0) > 0.001 then Ada.Text_IO.Put ("Value "); Ada.Float_Text_IO.Put (Value, Fore => 0, Aft => 3, Exp => 0); Ada.Text_IO.Put_Line (" is not 24!"); goto GET_EXP; else Ada.Text_IO.Put_Line ("You won!"); Ada.Text_IO.Put_Line ("Enter N for a new game, or try another solution."); goto GET_EXP; end if; end;
end Game_24;</lang>
- Output:
24 Game - Enter Q to Quit - Enter N for New digits Note: Operators are evaluated left-to-right (use parentheses to override) Generating 4 digits... Your Digits: 2 9 5 9 Enter your Expression: 9+9+5-2 Value 21.000 is not 24! Your Digits: 2 9 5 9 Enter your Expression: N Generating 4 digits... Your Digits: 7 7 1 3 Enter your Expression: (7-1)*(7-3) You won! Enter N for a new game, or try another solution.
APL
<lang APL>tfgame←{⎕IO←1
⎕←d←?⍵⍴9 i←⍞ u[⍋u←{⍎¨⍣(0≠≢⍵)⊢⍵}(i∊'1234567890')⊆i]≢d[⍋d]:'nope' ~∧/((~b←i∊'1234567890')/i)∊'+-×÷()':'nope' 24≠⍎i:'nope' 'Yeah!'
}</lang>
- Output:
tfgame 4 6 9 4 5 6+9+4+5 Yeah! tfgame 6 4 9 7 9 1 1 Ummm... I'm too tired. nope
Argile
<lang Argile>use std, array, list
do
generate random digits show random digits let result = parse expression (get input line) if result != ERROR if some digits are unused print "Wrong ! (you didn't use all digits)" ; failure++ else if result == 24.0 print "Correct !" ; success++ else print "Wrong ! (you got "result")" ; failure++ while play again ?
print "success:"success" failure:"failure" total:"(success+failure) as int
let success = 0, failure = 0.
.: generate random digits :.
our nat seed = 0xc6f31 (: default seed when /dev/urandom doesn't exist :) let urandom = fopen "/dev/urandom" "r" if urandom isn't nil fread &seed size of seed 1 urandom fclose urandom Cfunc srandom seed seed = (Cfunc random) as nat for each (val int d) from 0 to 3 digits[d] = '1' + (seed % 9) seed /= 9
let digits be an array of 4 byte
.: show random digits :.
print "Enter an expression that equates to 24 using only all these digits:" printf "%c , %c , %c , %c\n"(digits[0])(digits[1])(digits[2])(digits[3]) printf "24 = "
.: some digits are unused :. -> bool
for each (val int d) from 0 to 3 return true if digits[d] != '\0' false
.: get input line :. -> text
our array of 64 byte line Cfunc fgets (line) (size of line) (stdin) let int i for (i = 0) (line[i] != 0) (i++) line[i] = '\0' if (line[i] == '\n') line as text
.: play again ? :. -> bool
while true printf "Play again ? (y/n) " ; Cfunc fflush stdout let answer = get input line switch answer[0] case 'n' {return false} case 'y' {return true } default {continue } false
=: ERROR := -> real {-32202.0}
.: parse expression <text expr> :. -> real
let x = 0.0, x_is_set = false, op = ' '. let stack be a list of State ; class State {byte op; real x} for (stack = nil) (*expr != 0) (expr++) switch *expr case '+' ; case '-' ; case '*' ; case '/' error "bad syntax" if not x_is_set
op = *expr
case '1' ; case '2' ; case '3' ; case '4' ; case '5' case '6' ; case '7' ; case '8' ; case '9'
error "missing operator" if (x_is_set and op == ' ') error "unavailable digit" unless consume digit expr[0] do operation with (expr[0] - '0') as real
case (Cgen "'('")
error "missing operator" if (op == ' ' but x_is_set) (new list (new State) (code of del State())) << stack op = ' ' ; x_is_set = false (: start fresh state :)
case (Cgen "')'") error "mismatched parenthesis" if stack is nil
error "wrong syntax" if not x_is_set let y = x x = stack.data.x ; op = stack.data.op delete pop stack do operation with y
default {error "disallowed character"}
.:new State :. -> State {let s=new(State); s.x=x; s.op=op; s} .:del State <State s>:. { free s } .:do operation with <real y>:. switch op
case '+' {x += y} case '-' {x -= y} case '*' {x *= y} case '/' {x /= y} default {x = y; x_is_set = true}
op = ' ' =:error<text msg>:= ->real {eprint "Error: "msg" at ["expr"]";return ERROR} .:consume digit <byte b>:. -> bool for each (val int d) from 0 to 3 if digits[d] == b digits[d] = '\0' return true false
if stack isn't nil delete all stack error "unclosed parenthesis" return x
</lang> compile with: arc 24_game.arg -o 24_game.c && gcc 24_game.c -o 24_game /usr/lib/libargrt.a
ARM Assembly
<lang ARM Assembly> /* ARM assembly Raspberry PI */ /* program game24.s */
/* REMARK 1 : this program use routines in a include file
see task Include a file language arm assembly for the routine affichageMess conversion10 see at end of this program the instruction include */
/* for constantes see task include a file in arm assembly */ /************************************/ /* Constantes */ /************************************/ .include "../constantes.inc" .equ STDIN, 0 @ Linux input console .equ READ, 3 @ Linux syscall .equ NBDIGITS, 4 @ digits number .equ TOTAL, 24 .equ BUFFERSIZE, 100 .equ STACKSIZE, 10 @ operator and digits number items in stacks
/*********************************/
/* Initialized data */
/*********************************/
.data
szMessRules: .ascii "24 Game\n"
.ascii "The program will display four randomly-generated \n" .ascii "single-digit numbers and will then prompt you to enter\n" .ascii "an arithmetic expression followed by <enter> to sum \n" .ascii "the given numbers to 24.\n" .asciz "Exemple : 9+8+3+4 or (7+5)+(3*4) \n\n"
szMessExpr: .asciz "Enter your expression (or type (q)uit to exit or (n) for other digits): \n" //szMessErrChoise: .asciz "invalid choice.\n " szMessDigits: .asciz "The four digits are @ @ @ @ and the score is 24. \n" szMessNoDigit: .asciz "Error : One digit is not in digits list !! \n" szMessSameDigit: .asciz "Error : Two digits are same !! \n" szMessOK: .asciz "It is OK. \n" szMessNotOK: .asciz "Error, it is not ok total = @ \n" szMessErrOper: .asciz "Unknow Operator (+,-,$,/,(,)) \n" szMessNoparen: .asciz "no opening parenthesis !! \n" szMessErrParen: .asciz "Error parenthesis number !! \n" szMessNoalldigits: .asciz "One or more digits not used !!\n" szMessNewGame: .asciz "New game (y/n) ? \n" szCarriageReturn: .asciz "\n" .align 4 iGraine: .int 123456 /*********************************/ /* UnInitialized data */ /*********************************/ .bss sZoneConv: .skip 24 sBuffer: .skip BUFFERSIZE iTabDigit: .skip 4 * NBDIGITS iTabTopDigit: .skip 4 * NBDIGITS /*********************************/ /* code section */ /*********************************/ .text .global main main: @ entry of program
ldr r0,iAdrszMessRules @ display rules bl affichageMess
1:
mov r3,#0 ldr r12,iAdriTabDigit ldr r11,iAdriTabTopDigit ldr r5,iAdrszMessDigits
2: @ loop generate random digits
mov r0,#8 bl genereraleas add r0,r0,#1 str r0,[r12,r3,lsl #2] @ store in table mov r1,#0 str r1,[r11,r3,lsl #2] @ raz top table ldr r1,iAdrsZoneConv bl conversion10 @ call decimal conversion mov r2,#0 strb r2,[r1,r0] @ reduce size display area with zéro final mov r0,r5 ldr r1,iAdrsZoneConv @ insert conversion in message bl strInsertAtCharInc mov r5,r0 add r3,r3,#1 cmp r3,#NBDIGITS @ end ? blt 2b @ no -> loop mov r0,r5 bl affichageMess
3: @ loop human entry
ldr r0,iAdrszMessExpr bl affichageMess bl saisie @ entry cmp r0,#'q' beq 100f cmp r0,#'Q' beq 100f cmp r0,#'n' beq 1b cmp r0,#'N' beq 1b bl evalExpr @ expression evaluation cmp r0,#0 @ ok ? bne 3b @ no - > loop
10: @ display new game ?
ldr r0,iAdrszCarriageReturn bl affichageMess ldr r0,iAdrszMessNewGame bl affichageMess bl saisie cmp r0,#'y' beq 1b cmp r0,#'Y' beq 1b
100: @ standard end of the program
mov r0, #0 @ return code mov r7, #EXIT @ request to exit program svc #0 @ perform the system call
iAdrszCarriageReturn: .int szCarriageReturn iAdrszMessRules: .int szMessRules iAdrszMessDigits: .int szMessDigits iAdrszMessExpr: .int szMessExpr iAdrszMessNewGame: .int szMessNewGame iAdrsZoneConv: .int sZoneConv iAdriTabDigit: .int iTabDigit iAdriTabTopDigit: .int iTabTopDigit /******************************************************************/ /* evaluation expression */ /******************************************************************/ /* r0 return 0 if ok -1 else */ evalExpr:
push {r1-r11,lr} @ save registers mov r0,#0 ldr r1,iAdriTabTopDigit mov r2,#0
1: @ loop init table top digits
str r0,[r1,r2,lsl #2] add r2,r2,#1 cmp r2,#NBDIGITS blt 1b sub sp,sp,#STACKSIZE * 4 @ stack operator mov fp,sp sub sp,sp,#STACKSIZE * 4 @ stack digit mov r1,sp ldr r10,iAdrsBuffer mov r8,#0 @ indice character in buffer mov r7,#0 @ indice digits stack mov r2,#0 @ indice operator stack
1: @ begin loop
ldrb r9,[r10,r8] cmp r9,#0xA @ end expression ? beq 90f cmp r9,#' ' @ space ? addeq r8,r8,#1 @ loop beq 1b cmp r9,#'(' @ left parenthesis -> store in operator stack streq r9,[fp,r2,lsl #2] addeq r2,r2,#1 addeq r8,r8,#1 @ and loop beq 1b cmp r9,#')' @ right parenthesis ? bne 3f mov r0,fp @ compute operator stack until left parenthesis sub r2,r2,#1
2:
ldr r6,[fp,r2,lsl #2] cmp r6,#'(' @ left parenthesis addeq r8,r8,#1 @ end ? beq 1b @ and loop sub r7,r7,#1 @ last digit mov r3,r7 bl compute sub r2,r2,#1 cmp r2,#0 bge 2b ldr r0,iAdrszMessNoparen @ no left parenthesis in stack bl affichageMess mov r0,#-1 b 100f
3:
cmp r9,#'+' @ addition beq 4f cmp r9,#'-' @ soustraction beq 4f cmp r9,#'*' @ multiplication beq 4f cmp r9,#'/' @ division beq 4f
b 5f @ not operator
4: @ control priority and depile stacks
mov r0,fp mov r3,r7 mov r4,r9 bl depileOper mov r7,r3 add r8,r8,#1 b 1b @ and loop
5: @ digit
sub r9,r9,#0x30 mov r0,r9 bl digitControl cmp r0,#0 @ error ? bne 100f str r9,[r1,r7,lsl #2] @ store digit in digits stack add r7,r7,#1
add r8,r8,#1 beq 1b
b 100f
90: @ compute all stack operators
mov r0,fp sub r7,r7,#1
91:
subs r2,r2,#1 blt 92f mov r3,r7 bl compute sub r7,r7,#1 b 91b
92:
ldr r0,[r1] @ total = first value on digits stack cmp r0,#TOTAL @ control total beq 93f @ ok ldr r1,iAdrsZoneConv bl conversion10 @ call decimal conversion mov r2,#0 strb r2,[r1,r0] ldr r0,iAdrszMessNotOK ldr r1,iAdrsZoneConv @ insert conversion in message bl strInsertAtCharInc bl affichageMess mov r0,#-1 b 100f
93: @ control use all digits
ldr r1,iAdriTabTopDigit mov r2,#0
94: @ begin loop
ldr r0,[r1,r2,lsl #2] @ load top cmp r0,#0 bne 95f ldr r0,iAdrszMessNoalldigits bl affichageMess mov r0,#-1 b 100f
95:
add r2,r2,#1 cmp r2,#NBDIGITS blt 94b
96: @ display message OK
ldr r0,iAdrszMessOK bl affichageMess mov r0,#0 b 100f
100:
add sp,sp,#80 @ stack algnement pop {r1-r11,lr} bx lr @ return
iAdrszMessNoparen: .int szMessNoparen iAdrszMessNotOK: .int szMessNotOK iAdrszMessOK: .int szMessOK iAdrszMessNoalldigits: .int szMessNoalldigits /******************************************************************/ /* depile operator */ /******************************************************************/ /* r0 operator stack address */ /* r1 digits stack address */ /* r2 operator indice */ /* r3 digits indice */ /* r4 operator */ /* r2 return a new operator indice */ /* r3 return a new digits indice */ depileOper:
push {r4-r8,lr} @ save registers cmp r2,#0 @ first operator ? beq 60f sub r5,r2,#1
1:
ldr r6,[r0,r5,lsl #2] @ load stack operator cmp r6,r4 @ same operators beq 50f cmp r6,#'*' @ multiplication beq 50f cmp r6,#'/' @ division beq 50f cmp r6,#'-' @ soustraction beq 50f b 60f
50: @ depile operators stack and compute
sub r2,r2,#1 sub r3,r3,#1 bl compute sub r5,r5,#1 cmp r5,#0 bge 1b
60:
str r4,[r0,r2,lsl #2] @ add operator in stack add r2,r2,#1
100:
pop {r4-r8,lr} bx lr @ return
/******************************************************************/ /* compute */ /******************************************************************/ /* r0 operator stack address */ /* r1 digits stack address */ /* r2 operator indice */ /* r3 digits indice */ compute:
push {r1-r8,lr} @ save registers ldr r6,[r1,r3,lsl #2] @ load second digit sub r5,r3,#1 ldr r7,[r1,r5,lsl #2] @ load first digit ldr r8,[r0,r2,lsl #2] @ load operator cmp r8,#'+' bne 1f add r7,r7,r6 @ addition str r7,[r1,r5,lsl #2] b 100f
1:
cmp r8,#'-' bne 2f sub r7,r7,r6 @ soustaction str r7,[r1,r5,lsl #2] b 100f
2:
cmp r8,#'*' bne 3f @ multiplication mul r7,r6,r7 str r7,[r1,r5,lsl #2] b 100f
3:
cmp r8,#'/' bne 4f udiv r7,r7,r6 @ division str r7,[r1,r5,lsl #2] b 100f
4:
cmp r8,#'(' @ left parenthesis ? bne 5f ldr r0,iAdrszMessErrParen @ error bl affichageMess mov r0,#-1 b 100f
5:
ldr r0,iAdrszMessErrOper bl affichageMess mov r0,#-1
100:
pop {r1-r8,lr} bx lr @ return
iAdrszMessErrOper: .int szMessErrOper iAdrszMessErrParen: .int szMessErrParen /******************************************************************/ /* control digits */ /******************************************************************/ /* r0 return 0 if OK 1 if not digit */ digitControl:
push {r1-r4,lr} @ save registers ldr r1,iAdriTabTopDigit ldr r2,iAdriTabDigit mov r3,#0
1:
ldr r4,[r2,r3,lsl #2] @ load digit cmp r0,r4 @ equal ? beq 2f @ yes add r3,r3,#1 @ no -> loop cmp r3,#NBDIGITS @ end ? blt 1b ldr r0,iAdrszMessNoDigit @ error bl affichageMess mov r0,#1 b 100f
2: @ control prev use
ldr r4,[r1,r3,lsl #2] cmp r4,#0 beq 3f add r3,r3,#1 cmp r3,#NBDIGITS blt 1b ldr r0,iAdrszMessSameDigit bl affichageMess mov r0,#1 b 100f
3:
mov r4,#1 str r4,[r1,r3,lsl #2] mov r0,#0
100:
pop {r1-r4,lr} bx lr @ return
iAdrszMessNoDigit: .int szMessNoDigit iAdrszMessSameDigit: .int szMessSameDigit /******************************************************************/ /* string entry */ /******************************************************************/ /* r0 return the first character of human entry */ saisie:
push {r1-r7,lr} @ save registers mov r0,#STDIN @ Linux input console ldr r1,iAdrsBuffer @ buffer address mov r2,#BUFFERSIZE @ buffer size mov r7,#READ @ request to read datas svc 0 @ call system ldr r1,iAdrsBuffer @ buffer address ldrb r0,[r1] @ load first character
100:
pop {r1-r7,lr} bx lr @ return
iAdrsBuffer: .int sBuffer /***************************************************/ /* Generation random number */ /***************************************************/ /* r0 contains limit */ genereraleas:
push {r1-r4,lr} @ save registers ldr r4,iAdriGraine ldr r2,[r4] ldr r3,iNbDep1 mul r2,r3,r2 ldr r3,iNbDep2 add r2,r2,r3 str r2,[r4] @ maj de la graine pour l appel suivant cmp r0,#0 beq 100f add r1,r0,#1 @ divisor mov r0,r2 @ dividende bl division mov r0,r3 @ résult = remainder
100: @ end function
pop {r1-r4,lr} @ restaur registers bx lr @ return
/*****************************************************/ iAdriGraine: .int iGraine iNbDep1: .int 0x343FD iNbDep2: .int 0x269EC3 /***************************************************/ /* ROUTINES INCLUDE */ /***************************************************/ .include "../affichage.inc" </lang>
24 Game The program will display four randomly-generated single-digit numbers and will then prompt you to enter an arithmetic expression followed by <enter> to sum the given numbers to 24. Exemple : 9+8+3+4 or (7+5)+(3*4) The four digits are 5 1 1 5 and the score is 24. Enter your expression (or type (q)uit to exit or (n) for other digits): n The four digits are 8 2 5 3 and the score is 24. Enter your expression (or type (q)uit to exit or (n) for other digits): (8*2)+5+3 It is OK. New game (y/n) ?
AutoHotkey
<lang autohotkey>AutoExecute:
Title := "24 Game" Gui, -MinimizeBox Gui, Add, Text, w230 vPuzzle Gui, Add, Edit, wp vAnswer Gui, Add, Button, w70, &Generate Gui, Add, Button, x+10 wp Default, &Submit Gui, Add, Button, x+10 wp, E&xit
ButtonGenerate: ; new set of numbers
Loop, 4 Random, r%A_Index%, 1, 9 Puzzle = %r1%, %r2%, %r3%, and %r4% GuiControl,, Puzzle, The numbers are: %Puzzle% - Good luck! GuiControl,, Answer ; empty the edit box ControlFocus, Edit1 Gui, -Disabled Gui, Show,, %Title%
Return ; end of auto execute section
ButtonSubmit: ; check solution
Gui, Submit, NoHide Gui, +Disabled
; check numbers used RegExMatch(Answer, "(\d)\D+(\d)\D+(\d)\D+(\d)", $) ListPuzzle := r1 "," r2 "," r3 "," r4 ListAnswer := $1 "," $2 "," $3 "," $4 Sort, ListPuzzle, D, Sort, ListAnswer, D, If Not ListPuzzle = ListAnswer { MsgBox, 48, Error - %Title%, Numbers used!`n%Answer% Goto, TryAgain }
; check operators used StringReplace, $, $, +,, All StringReplace, $, $, -,, All StringReplace, $, $, *,, All StringReplace, $, $, /,, All StringReplace, $, $, (,, All StringReplace, $, $, ),, All Loop, 9 StringReplace, $, $, %A_Index%,, All If StrLen($) > 0 Or InStr(Answer, "**") Or InStr(Answer, "//") Or InStr(Answer, "++") Or InStr(Answer, "--") { MsgBox, 48, Error - %Title%, Operators used!`n%Answer% Goto, TryAgain }
; check result Result := Eval(Answer) If Not Result = 24 { MsgBox, 48, Error - %Title%, Result incorrect!`n%Result% Goto, TryAgain }
; if we are sill here MsgBox, 4, %Title%, Correct solution! Play again? IfMsgBox, Yes Gosub, ButtonGenerate Else ExitApp
Return
TryAgain: ; alternative ending of routine ButtonSubmit
ControlFocus, Edit1 Gui, -Disabled Gui, Show
Return
GuiClose:
GuiEscape:
ButtonExit:
ExitApp
Return
- ---------------------------------------------------------------------------
Eval(Expr) { ; evaluate expression using separate AHK process
- ---------------------------------------------------------------------------
; credit for this function goes to AutoHotkey forum member Laszlo ; http://www.autohotkey.com/forum/topic9578.html ;----------------------------------------------------------------------- static File := "24$Temp.ahk"
; delete old temporary file, and write new FileDelete, %File% FileContent := "#NoTrayIcon`r`n" . "FileDelete, " File "`r`n" . "FileAppend, `% " Expr ", " File "`r`n" FileAppend, %FileContent%, %File%
; run AHK to execute temp script, evaluate expression RunWait, %A_AhkPath% %File%
; get result FileRead, Result, %File% FileDelete, %File% Return, Result
}</lang>
AutoIt
<lang AutoIt>
- AutoIt Script Example
- by Daniel Barnes
- spam me at djbarnes at orcon dot net dot en zed
- 13/08/2012
- Choose four random digits (1-9) with repetitions allowed
global $digits FOR $i = 1 TO 4 $digits &= Random(1,9,1) NEXT
While 1 main() WEnd
Func main() $text = "Enter an equation (using all of, and only, the single digits "&$digits &")"&@CRLF $text &= "which evaluates to exactly 24. Only multiplication (*) division (/)"&@CRLF $text &= "addition (+) and subtraction (-) operations and parentheses are allowed:" $input = InputBox ("24 Game",$text,"","",400,150) If @error Then exit
;remove any spaces in input $input = StringReplace($input," ","")
;check correct characters were used For $i = 1 To StringLen($input) $chr = StringMid($input,$i,1) If Not StringInStr("123456789*/+-()",$chr) Then MsgBox (0, "ERROR","Invalid character used: '"&$chr&"'") return endif Next
;validate the equation uses all of the 4 characters, and nothing else $test = $input $test = StringReplace($test,"(","") $test = StringReplace($test,")","")
;validate the length of the input - if its not 7 characters long then the user has done something wrong If StringLen ($test) <> 7 Then MsgBox (0,"ERROR","The equation "&$test&" is invalid") return endif
$test = StringReplace($test,"/","") $test = StringReplace($test,"*","") $test = StringReplace($test,"-","") $test = StringReplace($test,"+","")
For $i = 1 To StringLen($digits) $digit = StringMid($digits,$i,1) For $ii = 1 To StringLen($test) If StringMid($test,$ii,1) = $digit Then $test = StringLeft($test,$ii-1) & StringRight($test,StringLen($test)-$ii) ExitLoop endif Next Next If $test <> "" Then MsgBox (0, "ERROR", "The equation didn't use all 4 characters, and nothing else!") return endif
$try = Execute($input)
If $try = 24 Then MsgBox (0, "24 Game","Well done. Your equation ("&$input&") = 24!") Exit Else MsgBox (0, "24 Game","Fail. Your equation ("&$input&") = "&$try&"!") return endif EndFunc </lang>
BBC BASIC
<lang bbcbasic> REM Choose four random digits (1-9) with repetitions allowed:
DIM digits%(4), check%(4) FOR choice% = 1 TO 4 digits%(choice%) = RND(9) NEXT choice% REM Prompt the player: PRINT "Enter an equation (using all of, and only, the single digits "; FOR index% = 1 TO 4 PRINT ; digits%(index%) ; IF index%<>4 PRINT " " ; NEXT PRINT ")" PRINT "which evaluates to exactly 24. Only multiplication (*), division (/)," PRINT "addition (+) & subtraction (-) operations and parentheses are allowed:" INPUT "24 = " equation$ REPEAT REM Check that the correct digits are used: check%() = 0 FOR char% = 1 TO LEN(equation$) digit% = INSTR("0123456789", MID$(equation$, char%, 1)) - 1 IF digit% >= 0 THEN FOR index% = 1 TO 4 IF digit% = digits%(index%) THEN IF NOT check%(index%) check%(index%) = TRUE : EXIT FOR ENDIF NEXT index% IF index% > 4 THEN PRINT "Sorry, you used the illegal digit "; digit% EXIT REPEAT ENDIF ENDIF NEXT char% FOR index% = 1 TO 4 IF NOT check%(index%) THEN PRINT "Sorry, you failed to use the digit " ; digits%(index%) EXIT REPEAT ENDIF NEXT index% REM Check that no pairs of digits are used: FOR pair% = 11 TO 99 IF INSTR(equation$, STR$(pair%)) THEN PRINT "Sorry, you may not use a pair of digits "; pair% EXIT REPEAT ENDIF NEXT pair% REM Check whether the equation evaluates to 24: ON ERROR LOCAL PRINT "Sorry, there was an error in the equation" : EXIT REPEAT result = EVAL(equation$) RESTORE ERROR IF result = 24 THEN PRINT "Congratulations, you succeeded in the task!" ELSE PRINT "Sorry, your equation evaluated to " ; result " rather than 24!" ENDIF UNTIL TRUE INPUT '"Play again", answer$ IF LEFT$(answer$,1) = "y" OR LEFT$(answer$,1) = "Y" THEN CLS : RUN QUIT</lang>
Befunge
<lang befunge>v > > >> v 2 2 1234 4 ^1?3^4 >8*00p10p> >? ?5> 68*+00g10gpv
v9?7v6 0 8 0 > > >> ^ g ^p00 _v# `\*49:+1 <
_>"rorrE",,,,,$ >~:67*-!#v_:167*+-!#v_:95*-!#v_:295*+-!#v_:586*+\`#v_:97*2--!#v
$ $ $ $ : $ * + - / 1 :
^ < < < < 8 .
6 6 * 4 + * \ - ` > v_v " ^ < _v e
^ _^#+*28:p2\*84\-*86g2:-+*441< s
o L > 1 |-*49"#< | -*84gg01g00<p00*84<v < >00g:1+00p66*`#^_ "niW">:#,_@
</lang> The code functions by placing the 4 randomly generated numbers into the points labelled 1,2,3,4. In order to play, press the corresponding label to draw that number onto the stack, then press the corresponding operation (+,-,*,/) to perform it on the stack elements postfix-wise according to the rules of befunge (i.e. pop the values operate and push the answer back to the stack). When you wish to check your answer enter "=" and it will perform the checks to ensure that you haven't performed any illegal operations, that you have used all four numbers and that your final value is 24.
Unfortunately, due to the lack of floating-point arithmetic in befunge, divide will result in the answer truncated to an integer.
Example: 6566
213/-4*=
- Output:
24 Win
Bracmat
<lang Bracmat> ( 24-game
= m-w m-z 4numbers answer expr numbers , seed get-random convertBinaryMinusToUnary , convertDivisionToMultiplication isExpresssion reciprocal . (seed=.!arg:(~0:~/#?m-w.~0:~/#?m-z)) & seed$!arg & ( get-random = . 36969*mod$(!m-z.65536)+div$(!m-z.65536):?m-z & 18000*mod$(!m-w.65536)+div$(!m-w.65536):?m-w & mod$(!m-z*65536+!m-w.9)+1 ) & ( convertBinaryMinusToUnary = a z . @(!arg:%?a "-" ?z) & str$(!a "+-1*" convertBinaryMinusToUnary$!z) | !arg ) & (reciprocal=.!arg^-1) & ( convertDivisionToMultiplication = a z . @(!arg:?a "/" ?z) & str$(!a "*reciprocal$" convertDivisionToMultiplication$!z) | !arg ) & ( isExpresssion = A Z expr . @( !arg : ?A ("+"|"-"|"*"|"/") ( ?Z & isExpresssion$!A & isExpresssion$!Z ) ) | !numbers:?A !arg ?Z & !A !Z:?numbers | ( @(!arg:"(" ?expr ")") | @(!arg:(" "|\t) ?expr) | @(!arg:?expr (" "|\t)) ) & isExpresssion$!expr ) & out $ "Enter an expression that evaluates to 24 by combining the following numbers." & out$"You may only use the operators + - * /" & out$"Parentheses and spaces are allowed." & whl ' ( get-random$() get-random$() get-random$() get-random$ : ?4numbers & out$!4numbers & whl ' ( get'(,STR):?expr:~ & !4numbers:?numbers & ~(isExpresssion$!expr&!numbers:) & out $ ( str $ ( "[" !expr "] is not a valid expression. Try another expression." ) ) ) & !expr:~ & convertBinaryMinusToUnary$!expr:?expr & convertDivisionToMultiplication$!expr:?expr & get$(!expr,MEM):?answer & out$(str$(!expr " = " !answer)) & !answer : ( 24&out$Right! | #&out$Wrong! ) & out$"Try another one:" ) & out$bye )
& 24-game$(13.14) & ;</lang>
Enter an expression that evaluates to 24 by combining the following numbers. You may only use the operators + - * / Parentheses and spaces are allowed. 4 2 2 7 4*7 - 2-2 4*7 +-1* 2+-1*2 = 24 Right! Try another one: 4 7 9 8 ((4) *(8 - (9- 7)) [((4) *(8 - (9- 7))] is not a valid expression. Try another expression. ((4) *(8 - (9- 7))) ((4) *(8 +-1* (9+-1* 7))) = 24 Right! Try another one: 9 5 8 5 5 * 5 - (9 - 8) 5 * 5 +-1* (9 +-1* 8) = 24 Right! Try another one: 5 9 7 8 5*8 - 9 - 7 5*8 +-1* 9 +-1* 7 = 24 Right! Try another one: 7 8 6 2 8 * ((7 - 6) + 2) 8 * ((7 +-1* 6) + 2) = 24 Right! Try another one: 8 6 8 1 8 * (1 + 8 - 6) 8 * (1 + 8 +-1* 6) = 24 Right! Try another one: 8 2 2 4 8 * (2 + 4)/2 8 * (2 + 4)*reciprocal$2 = 24 Right! Try another one: 8 4 6 7 bye
C
Simple recursive descent parser. It doesn't have a real lexer, because all tokens are single character (digits, operators and parens). Code is a little too long. <lang C>#include <stdio.h>
- include <ctype.h>
- include <stdlib.h>
- include <setjmp.h>
- include <time.h>
jmp_buf ctx; const char *msg;
enum { OP_NONE = 0, OP_NUM, OP_ADD, OP_SUB, OP_MUL, OP_DIV };
typedef struct expr_t *expr, expr_t; struct expr_t { int op, val, used; expr left, right; };
- define N_DIGITS 4
expr_t digits[N_DIGITS];
void gen_digits() { int i; for (i = 0; i < N_DIGITS; i++) digits[i].val = 1 + rand() % 9; }
- define MAX_INPUT 64
char str[MAX_INPUT]; int pos;
- define POOL_SIZE 8
expr_t pool[POOL_SIZE]; int pool_ptr;
void reset() { int i; msg = 0; pool_ptr = pos = 0; for (i = 0; i < POOL_SIZE; i++) { pool[i].op = OP_NONE; pool[i].left = pool[i].right = 0; } for (i = 0; i < N_DIGITS; i++) digits[i].used = 0; }
/* longish jumpish back to input cycle */ void bail(const char *s) { msg = s; longjmp(ctx, 1); }
expr new_expr() { if (pool_ptr < POOL_SIZE) return pool + pool_ptr++; return 0; }
/* check next input char */ int next_tok() { while (isspace(str[pos])) pos++; return str[pos]; }
/* move input pointer forward */ int take() { if (str[pos] != '\0') return ++pos; return 0; }
/* BNF(ish) expr = term { ("+")|("-") term } term = fact { ("*")|("/") expr } fact = number | '(' expr ')'
- /
expr get_fact(); expr get_term(); expr get_expr();
expr get_expr() { int c; expr l, r, ret; if (!(ret = get_term())) bail("Expected term"); while ((c = next_tok()) == '+' || c == '-') { if (!take()) bail("Unexpected end of input"); if (!(r = get_term())) bail("Expected term");
l = ret; ret = new_expr(); ret->op = (c == '+') ? OP_ADD : OP_SUB; ret->left = l; ret->right = r; } return ret; }
expr get_term() { int c; expr l, r, ret; ret = get_fact(); while((c = next_tok()) == '*' || c == '/') { if (!take()) bail("Unexpected end of input");
r = get_fact(); l = ret; ret = new_expr(); ret->op = (c == '*') ? OP_MUL : OP_DIV; ret->left = l; ret->right = r; } return ret; }
expr get_digit() { int i, c = next_tok(); expr ret; if (c >= '0' && c <= '9') { take(); ret = new_expr(); ret->op = OP_NUM; ret->val = c - '0'; for (i = 0; i < N_DIGITS; i++) if (digits[i].val == ret->val && !digits[i].used) { digits[i].used = 1; return ret; } bail("Invalid digit"); } return 0; }
expr get_fact() { int c; expr l = get_digit(); if (l) return l; if ((c = next_tok()) == '(') { take(); l = get_expr(); if (next_tok() != ')') bail("Unbalanced parens"); take(); return l; } return 0; }
expr parse() { int i; expr ret = get_expr(); if (next_tok() != '\0') bail("Trailing garbage"); for (i = 0; i < N_DIGITS; i++) if (!digits[i].used) bail("Not all digits are used"); return ret; }
typedef struct frac_t frac_t, *frac; struct frac_t { int denom, num; };
int gcd(int m, int n) { int t; while (m) { t = m; m = n % m; n = t; } return n; }
/* evaluate expression tree. result in fraction form */ void eval_tree(expr e, frac res) { frac_t l, r; int t; if (e->op == OP_NUM) { res->num = e->val; res->denom = 1; return; }
eval_tree(e->left, &l); eval_tree(e->right, &r);
switch(e->op) { case OP_ADD: res->num = l.num * r.denom + l.denom * r.num; res->denom = l.denom * r.denom; break; case OP_SUB: res->num = l.num * r.denom - l.denom * r.num; res->denom = l.denom * r.denom; break; case OP_MUL: res->num = l.num * r.num; res->denom = l.denom * r.denom; break; case OP_DIV: res->num = l.num * r.denom; res->denom = l.denom * r.num; break; } if ((t = gcd(res->denom, res->num))) { res->denom /= t; res->num /= t; } }
void get_input() { int i; reinput: reset(); printf("\nAvailable digits are:"); for (i = 0; i < N_DIGITS; i++) printf(" %d", digits[i].val); printf(". Type an expression and I'll check it for you, or make new numbers.\n" "Your choice? [Expr/n/q] ");
while (1) { for (i = 0; i < MAX_INPUT; i++) str[i] = '\n'; fgets(str, MAX_INPUT, stdin); if (*str == '\0') goto reinput; if (str[MAX_INPUT - 1] != '\n') bail("string too long");
for (i = 0; i < MAX_INPUT; i++) if (str[i] == '\n') str[i] = '\0'; if (str[0] == 'q') { printf("Bye\n"); exit(0); } if (str[0] == 'n') { gen_digits(); goto reinput; } return; } }
int main() { frac_t f; srand(time(0));
gen_digits(); while(1) { get_input(); setjmp(ctx); /* if parse error, jump back here with err msg set */ if (msg) { /* after error jump; announce, reset, redo */ printf("%s at '%.*s'\n", msg, pos, str); continue; }
eval_tree(parse(), &f);
if (f.denom == 0) bail("Divide by zero"); if (f.denom == 1 && f.num == 24) printf("You got 24. Very good.\n"); else { if (f.denom == 1) printf("Eval to: %d, ", f.num); else printf("Eval to: %d/%d, ", f.num, f.denom); printf("no good. Try again.\n"); } } return 0; }</lang>
- Output:
Available digits are: 5 2 3 9. Type an expression and I'll check it for you, or make new numbers. Your choice? [Expr/n/q] 5*2*3/9 Eval to: 10/3, no good. Try again. Available digits are: 5 2 3 9. Type an expression and I'll check it for you, or make new numbers. Your choice? [Expr/n/q] (5*(2+3)-9 Unbalanced parens at '(5*(2+3)-9' Available digits are: 5 2 3 9. Type an expression and I'll check it for you, or make new numbers. Your choice? [Expr/n/q] 3*9-(5-2) You got 24. Very good. Available digits are: 5 2 3 9. Type an expression and I'll check it for you, or make new numbers. Your choice? [Expr/n/q] n Available digits are: 4 4 4 7. Type an expression and I'll check it for you, or make new numbers. Your choice? [Expr/n/q] q Bye
See 24 game/C
C#
See 24 game/CSharp
C++
This uses the C++11 standard to simplify several parts of the code. Input is given in RPN format.
<lang cpp>#include <random>
- include <iostream>
- include <stack>
- include <set>
- include <string>
- include <functional>
using namespace std;
class RPNParse { public:
stack<double> stk; multiset<int> digits;
void op(function<double(double,double)> f) { if(stk.size() < 2) throw "Improperly written expression"; int b = stk.top(); stk.pop(); int a = stk.top(); stk.pop(); stk.push(f(a, b)); }
void parse(char c) { if(c >= '0' && c <= '9') { stk.push(c - '0'); digits.insert(c - '0'); } else if(c == '+') op([](double a, double b) {return a+b;}); else if(c == '-') op([](double a, double b) {return a-b;}); else if(c == '*') op([](double a, double b) {return a*b;}); else if(c == '/') op([](double a, double b) {return a/b;}); }
void parse(string s) { for(int i = 0; i < s.size(); ++i) parse(s[i]); }
double getResult() { if(stk.size() != 1) throw "Improperly written expression"; return stk.top(); }
};
int main() {
random_device seed; mt19937 engine(seed()); uniform_int_distribution<> distribution(1, 9); auto rnd = bind(distribution, engine);
multiset<int> digits; cout << "Make 24 with the digits: "; for(int i = 0; i < 4; ++i) { int n = rnd(); cout << " " << n; digits.insert(n); } cout << endl;
RPNParse parser;
try { string input; getline(cin, input); parser.parse(input);
if(digits != parser.digits) cout << "Error: Not using the given digits" << endl; else { double r = parser.getResult(); cout << "Result: " << r << endl;
if(r > 23.999 && r < 24.001) cout << "Good job!" << endl; else cout << "Try again." << endl; } } catch(char* e) { cout << "Error: " << e << endl; } return 0;
}</lang>
- Output:
Make 24 with the digits: 1 4 9 9 9 9 + 4 * 1 + Result: 73 Try again. Make 24 with the digits: 3 9 9 2 9 9 + 3 2 * + Result: 24 Good job!
Ceylon
Be sure to import ceylon.random in you ceylon.module file. <lang ceylon>import ceylon.random { DefaultRandom }
class Rational(shared Integer numerator, shared Integer denominator = 1) satisfies Numeric<Rational> {
assert (denominator != 0);
Integer gcd(Integer a, Integer b) => if (b == 0) then a else gcd(b, a % b);
shared Rational inverted => Rational(denominator, numerator);
shared Rational simplified => let (largestFactor = gcd(numerator, denominator)) Rational(numerator / largestFactor, denominator / largestFactor);
divided(Rational other) => (this * other.inverted).simplified;
negated => Rational(-numerator, denominator).simplified;
plus(Rational other) => let (top = numerator*other.denominator + other.numerator*denominator, bottom = denominator * other.denominator) Rational(top, bottom).simplified;
times(Rational other) => Rational(numerator * other.numerator, denominator * other.denominator).simplified;
shared Integer integer => numerator / denominator; shared Float float => numerator.float / denominator.float;
string => denominator == 1 then numerator.string else "``numerator``/``denominator``";
shared actual Boolean equals(Object that) { if (is Rational that) { value simplifiedThis = this.simplified; value simplifiedThat = that.simplified; return simplifiedThis.numerator==simplifiedThat.numerator && simplifiedThis.denominator==simplifiedThat.denominator; } else { return false; } } }
interface Expression { shared formal Rational evaluate(); }
class NumberExpression(Rational number) satisfies Expression { evaluate() => number; string => number.string; }
class OperatorExpression(Expression left, Character operator, Expression right) satisfies Expression { shared actual Rational evaluate() { switch (operator) case ('*') { return left.evaluate() * right.evaluate(); } case ('/') { return left.evaluate() / right.evaluate(); } case ('-') { return left.evaluate() - right.evaluate(); } case ('+') { return left.evaluate() + right.evaluate(); } else { throw Exception("unknown operator ``operator``"); } }
string => "(``left.string`` ``operator.string`` ``right.string``)"; }
"A simplified top down operator precedence parser. There aren't any right
binding operators so we don't have to worry about that."
class PrattParser(String input) {
value tokens = input.replace(" ", ""); variable value index = -1;
shared Expression expression(Integer precedence = 0) { value token = advance(); variable value left = parseUnary(token); while (precedence < getPrecedence(peek())) { value nextToken = advance(); left = parseBinary(left, nextToken); } return left; }
Integer getPrecedence(Character op) => switch (op) case ('*' | '/') 2 case ('+' | '-') 1 else 0;
Character advance(Character? expected = null) { index++; value token = tokens[index] else ' '; if (exists expected, token != expected) { throw Exception("unknown character ``token``"); } return token; }
Character peek() => tokens[index + 1] else ' ';
Expression parseBinary(Expression left, Character operator) => let (right = expression(getPrecedence(operator))) OperatorExpression(left, operator, right);
Expression parseUnary(Character token) { if (token.digit) { assert (is Integer int = Integer.parse(token.string)); return NumberExpression(Rational(int)); } else if (token == '(') { value exp = expression(); advance(')'); return exp; } else { throw Exception("unknown character ``token``"); } } }
shared void run() {
value random = DefaultRandom();
function random4Numbers() => random.elements(1..9).take(4).sequence();
function isValidGuess(String input, {Integer*} allowedNumbers) { value allowedOperators = set { *"()+-/*" }; value extractedNumbers = input .split((Character ch) => ch in allowedOperators || ch.whitespace) .map((String element) => Integer.parse(element)) .narrow<Integer>(); if (extractedNumbers.any((Integer element) => element > 9)) { print("number too big!"); return false; } if (extractedNumbers.any((Integer element) => element < 1)) { print("number too small!"); return false; } if (extractedNumbers.sort(increasing) != allowedNumbers.sort(increasing)) { print("use all the numbers, please!"); return false; } if (!input.every((Character element) => element in allowedOperators || element.digit || element.whitespace)) { print("only digits and mathematical operators, please"); return false; } variable value leftParens = 0; for (c in input) { if (c == '(') { leftParens++; } else if (c == ')') { leftParens--; if (leftParens < 0) { break; } } } if (leftParens != 0) { print("unbalanced brackets!"); return false; } return true; }
function evaluate(String input) => let (parser = PrattParser(input), exp = parser.expression()) exp.evaluate();
print("Welcome to The 24 Game. Create a mathematical equation with four random numbers that evaluates to 24. You must use all the numbers once and only once, but in any order. Also, only + - / * and parentheses are allowed. For example: (1 + 2 + 3) * 4 Also: enter n for new numbers and q to quit. -----------------------------------------------");
value twentyfour = Rational(24);
while (true) {
value chosenNumbers = random4Numbers(); void pleaseTryAgain() => print("Sorry, please try again. (Your numbers are ``chosenNumbers``)");
print("Your numbers are ``chosenNumbers``. Please turn them into 24.");
while (true) { value line = process.readLine()?.trimmed; if (exists line) { if (line.uppercased == "Q") { // quit print("bye!"); return; } if (line.uppercased == "N") { // new game break; } if (isValidGuess(line, chosenNumbers)) { try { value result = evaluate(line); print("= ``result``"); if (result == twentyfour) { print("You did it!"); break; } else { pleaseTryAgain(); } } catch (Exception e) { print(e.message); pleaseTryAgain(); } } else { pleaseTryAgain(); } } } } }</lang>
Clojure
<lang Clojure> (ns rosettacode.24game)
(def ^:dynamic *luser* "You guessed wrong, or your input was not in prefix notation.")
(def ^:private start #(println "Your numbers are: " %1 ". Your goal is " %2 ".\n" "Use the ops [+ - * /] in prefix notation to reach" %2 ".\n" "q[enter] to quit."))
(defn play
([] (play 24)) ([goal] (play goal (repeatedly 4 #(inc (rand-int 9))))) ([goal gns] (start gns goal) (let [input (read-string (read-line)) flat (flatten input)] (println (if (and (re-find #"^\([\d\s+*/-]+\d?\)$" (pr-str flat)) (= (set gns) (set (filter integer? flat))) (= goal (eval input))) "You won the game!" *luser*)) (when (not= input 'q) (recur goal gns)))))
- * checks prefix form, then checks to see that the numbers used
- and the numbers generated by the game are the same.
</lang>
COBOL
<lang COBOL> >>SOURCE FORMAT FREE
- > This code is dedicated to the public domain
- > This is GNUCobol 2.0
identification division. program-id. twentyfour. environment division. configuration section. repository. function all intrinsic. data division. working-storage section. 01 p pic 999. 01 p1 pic 999. 01 p-max pic 999 value 38. 01 program-syntax pic x(494) value
- >statement = expression;
'001 001 000 n' & '002 000 004 =' & '003 005 000 n' & '004 000 002 ;'
- >expression = term, {('+'|'-') term,};
& '005 005 000 n' & '006 000 016 =' & '007 017 000 n' & '008 000 015 {' & '009 011 013 (' & '010 001 000 t' & '011 013 000 |' & '012 002 000 t' & '013 000 009 )' & '014 017 000 n' & '015 000 008 }' & '016 000 006 ;'
- >term = factor, {('*'|'/') factor,};
& '017 017 000 n' & '018 000 028 =' & '019 029 000 n' & '020 000 027 {' & '021 023 025 (' & '022 003 000 t' & '023 025 000 |' & '024 004 000 t' & '025 000 021 )' & '026 029 000 n' & '027 000 020 }' & '028 000 018 ;'
- >factor = ('(' expression, ')' | digit,);
& '029 029 000 n' & '030 000 038 =' & '031 035 037 (' & '032 005 000 t' & '033 005 000 n' & '034 006 000 t' & '035 037 000 |' & '036 000 000 n' & '037 000 031 )' & '038 000 030 ;'.
01 filler redefines program-syntax.
03 p-entry occurs 038. 05 p-address pic 999. 05 filler pic x. 05 p-definition pic 999. 05 p-alternate redefines p-definition pic 999. 05 filler pic x. 05 p-matching pic 999. 05 filler pic x. 05 p-symbol pic x.
01 t pic 999. 01 t-len pic 99 value 6. 01 terminal-symbols
pic x(210) value '01 + ' & '01 - ' & '01 * ' & '01 / ' & '01 ( ' & '01 ) '.
01 filler redefines terminal-symbols.
03 terminal-symbol-entry occurs 6. 05 terminal-symbol-len pic 99. 05 filler pic x. 05 terminal-symbol pic x(32).
01 nt pic 999. 01 nt-lim pic 99 value 5. 01 nonterminal-statements pic x(294) value
"000 ....,....,....,....,....,....,....,....,....," & "001 statement = expression; " & "005 expression = term, {('+'|'-') term,}; " & "017 term = factor, {('*'|'/') factor,}; " & "029 factor = ('(' expression, ')' | digit,); " & "036 digit; ".
01 filler redefines nonterminal-statements.
03 nonterminal-statement-entry occurs 5. 05 nonterminal-statement-number pic 999. 05 filler pic x. 05 nonterminal-statement pic x(45).
01 indent pic x(64) value all '| '. 01 interpreter-stack.
03 r pic 99. *> previous top of stack 03 s pic 99. *> current top of stack 03 s-max pic 99 value 32. 03 s-entry occurs 32. 05 filler pic x(2) value 'p='. 05 s-p pic 999. *> callers return address 05 filler pic x(4) value ' sc='. 05 s-start-control pic 999. *> sequence start address 05 filler pic x(4) value ' ec='. 05 s-end-control pic 999. *> sequence end address 05 filler pic x(4) value ' al='. 05 s-alternate pic 999. *> the next alternate 05 filler pic x(3) value ' r='. 05 s-result pic x. *> S success, F failure, N no result 05 filler pic x(3) value ' c='. 05 s-count pic 99. *> successes in a sequence 05 filler pic x(3) value ' x='. 05 s-repeat pic 99. *> repeats in a {} sequence 05 filler pic x(4) value ' nt='. 05 s-nt pic 99. *> current nonterminal
01 language-area.
03 l pic 99. 03 l-lim pic 99. 03 l-len pic 99 value 1. 03 nd pic 9. 03 number-definitions. 05 n occurs 4 pic 9. 03 nu pic 9. 03 number-use. 05 u occurs 4 pic x. 03 statement. 05 c occurs 32. 07 c9 pic 9.
01 number-validation.
03 p4 pic 99. 03 p4-lim pic 99 value 24. 03 permutations-4 pic x(96) value '1234' & '1243' & '1324' & '1342' & '1423' & '1432' & '2134' & '2143' & '2314' & '2341' & '2413' & '2431' & '3124' & '3142' & '3214' & '3241' & '3423' & '3432' & '4123' & '4132' & '4213' & '4231' & '4312' & '4321'. 03 filler redefines permutations-4. 05 permutation-4 occurs 24 pic x(4). 03 current-permutation-4 pic x(4). 03 cpx pic 9. 03 od1 pic 9. 03 od2 pic 9. 03 odx pic 9. 03 od-lim pic 9 value 4. 03 operator-definitions pic x(4) value '+-*/'. 03 current-operators pic x(3). 03 co3 pic 9. 03 rpx pic 9. 03 rpx-lim pic 9 value 4. 03 valid-rpn-forms pic x(28) value 'nnonono' & 'nnnonoo' & 'nnnoono' & 'nnnnooo'. 03 filler redefines valid-rpn-forms. 05 rpn-form occurs 4 pic x(7). 03 current-rpn-form pic x(7).
01 calculation-area.
03 osx pic 99. 03 operator-stack pic x(32). 03 oqx pic 99. 03 oqx1 pic 99. 03 output-queue pic x(32). 03 work-number pic s9999. 03 top-numerator pic s9999 sign leading separate. 03 top-denominator pic s9999 sign leading separate. 03 rsx pic 9. 03 result-stack occurs 8. 05 numerator pic s9999. 05 denominator pic s9999.
01 error-found pic x. 01 divide-by-zero-error pic x.
- > diagnostics
01 NL pic x value x'0A'. 01 NL-flag pic x value space. 01 display-level pic x value '0'. 01 loop-lim pic 9999 value 1500. 01 loop-count pic 9999 value 0. 01 message-area value spaces.
03 message-level pic x. 03 message-value pic x(128).
- > input and examples
01 instruction pic x(32) value spaces. 01 tsx pic 99. 01 tsx-lim pic 99 value 14. 01 test-statements.
03 filler pic x(32) value '1234;1 + 2 + 3 + 4'. 03 filler pic x(32) value '1234;1 * 2 * 3 * 4'. 03 filler pic x(32) value '1234;((1)) * (((2 * 3))) * 4'. 03 filler pic x(32) value '1234;((1)) * ((2 * 3))) * 4'. 03 filler pic x(32) value '1234;(1 + 2 + 3 + 4'. 03 filler pic x(32) value '1234;)1 + 2 + 3 + 4'. 03 filler pic x(32) value '1234;1 * * 2 * 3 * 4'. 03 filler pic x(32) value '5679;6 - (5 - 7) * 9'. 03 filler pic x(32) value '1268;((1 * (8 * 6) / 2))'. 03 filler pic x(32) value '4583;-5-3+(8*4)'. 03 filler pic x(32) value '4583;8 * 4 - 5 - 3'. 03 filler pic x(32) value '4583;8 * 4 - (5 + 3)'. 03 filler pic x(32) value '1223;1 * 3 / (2 - 2)'. 03 filler pic x(32) value '2468;(6 * 8) / 4 / 2'.
01 filler redefines test-statements.
03 filler occurs 14. 05 test-numbers pic x(4). 05 filler pic x. 05 test-statement pic x(27).
procedure division. start-twentyfour.
display 'start twentyfour' perform generate-numbers display 'type h <enter> to see instructions' accept instruction perform until instruction = spaces or 'q' evaluate true when instruction = 'h' perform display-instructions when instruction = 'n' perform generate-numbers when instruction(1:1) = 'm' move instruction(2:4) to number-definitions perform validate-number if divide-by-zero-error = space and 24 * top-denominator = top-numerator display number-definitions ' is solved by ' output-queue(1:oqx) else display number-definitions ' is not solvable' end-if when instruction = 'd0' or 'd1' or 'd2' or 'd3' move instruction(2:1) to display-level when instruction = 'e' display 'examples:' perform varying tsx from 1 by 1 until tsx > tsx-lim move spaces to statement move test-numbers(tsx) to number-definitions move test-statement(tsx) to statement perform evaluate-statement perform show-result end-perform when other move instruction to statement perform evaluate-statement perform show-result end-evaluate move spaces to instruction display 'instruction? ' with no advancing accept instruction end-perform
display 'exit twentyfour' stop run .
generate-numbers.
perform with test after until divide-by-zero-error = space and 24 * top-denominator = top-numerator compute n(1) = random(seconds-past-midnight) * 10 *> seed perform varying nd from 1 by 1 until nd > 4 compute n(nd) = random() * 10 perform until n(nd) <> 0 compute n(nd) = random() * 10 end-perform end-perform perform validate-number end-perform display NL 'numbers:' with no advancing perform varying nd from 1 by 1 until nd > 4 display space n(nd) with no advancing end-perform display space .
validate-number.
perform varying p4 from 1 by 1 until p4 > p4-lim move permutation-4(p4) to current-permutation-4 perform varying od1 from 1 by 1 until od1 > od-lim move operator-definitions(od1:1) to current-operators(1:1) perform varying od2 from 1 by 1 until od2 > od-lim move operator-definitions(od2:1) to current-operators(2:1) perform varying odx from 1 by 1 until odx > od-lim move operator-definitions(odx:1) to current-operators(3:1) perform varying rpx from 1 by 1 until rpx > rpx-lim move rpn-form(rpx) to current-rpn-form move 0 to cpx co3 move spaces to output-queue move 7 to oqx perform varying oqx1 from 1 by 1 until oqx1 > oqx if current-rpn-form(oqx1:1) = 'n' add 1 to cpx move current-permutation-4(cpx:1) to nd move n(nd) to output-queue(oqx1:1) else add 1 to co3 move current-operators(co3:1) to output-queue(oqx1:1) end-if end-perform end-perform perform evaluate-rpn if divide-by-zero-error = space and 24 * top-denominator = top-numerator exit paragraph end-if end-perform end-perform end-perform end-perform .
display-instructions.
display '1) Type h <enter> to repeat these instructions.' display '2) The program will display four randomly-generated' display ' single-digit numbers and will then prompt you to enter' display ' an arithmetic expression followed by <enter> to sum' display ' the given numbers to 24.' display ' The four numbers may contain duplicates and the entered' display ' expression must reference all the generated numbers and duplicates.' display ' Warning: the program converts the entered infix expression' display ' to a reverse polish notation (rpn) expression' display ' which is then interpreted from RIGHT to LEFT.' display ' So, for instance, 8*4 - 5 - 3 will not sum to 24.' display '3) Type n <enter> to generate a new set of four numbers.' display ' The program will ensure the generated numbers are solvable.' display '4) Type m#### <enter> (e.g. m1234) to create a fixed set of numbers' display ' for testing purposes.' display ' The program will test the solvability of the entered numbers.' display ' For example, m1234 is solvable and m9999 is not solvable.' display '5) Type d0, d1, d2 or d3 followed by <enter> to display none or' display ' increasingly detailed diagnostic information as the program evaluates' display ' the entered expression.' display '6) Type e <enter> to see a list of example expressions and results' display '7) Type <enter> or q <enter> to exit the program' .
show-result.
if error-found = 'y' or divide-by-zero-error = 'y' exit paragraph end-if display 'statement in RPN is' space output-queue evaluate true when top-numerator = 0 when top-denominator = 0 when 24 * top-denominator <> top-numerator display 'result (' top-numerator '/' top-denominator ') is not 24' when other display 'result is 24' end-evaluate .
evaluate-statement.
compute l-lim = length(trim(statement))
display NL 'numbers:' space n(1) space n(2) space n(3) space n(4) move number-definitions to number-use display 'statement is' space statement
move 1 to l move 0 to loop-count move space to error-found
move 0 to osx oqx move spaces to output-queue
move 1 to p move 1 to nt move 0 to s perform increment-s perform display-start-nonterminal perform increment-p
*>=================================== *> interpret ebnf *>=================================== perform until s = 0 or error-found = 'y'
evaluate true
when p-symbol(p) = 'n' and p-definition(p) = 000 *> a variable perform test-variable if s-result(s) = 'S' perform increment-l end-if perform increment-p
when p-symbol(p) = 'n' and p-address(p) <> p-definition(p) *> nonterminal reference move p to s-p(s) move p-definition(p) to p
when p-symbol(p) = 'n' and p-address(p) = p-definition(p) *> nonterminal definition perform increment-s perform display-start-nonterminal perform increment-p
when p-symbol(p) = '=' *> nonterminal control move p to s-start-control(s) move p-matching(p) to s-end-control(s) perform increment-p
when p-symbol(p) = ';' *> end nonterminal perform display-end-control perform display-end-nonterminal perform decrement-s if s > 0 evaluate true when s-result(r) = 'S' perform set-success when s-result(r) = 'F' perform set-failure end-evaluate move s-p(s) to p perform increment-p perform display-continue-nonterminal end-if
when p-symbol(p) = '{' *> start repeat sequence perform increment-s perform display-start-control move p to s-start-control(s) move p-alternate(p) to s-alternate(s) move p-matching(p) to s-end-control(s) move 0 to s-count(s) perform increment-p
when p-symbol(p) = '}' *> end repeat sequence perform display-end-control evaluate true when s-result(s) = 'S' *> repeat the sequence perform display-repeat-control perform set-nothing add 1 to s-repeat(s) move s-start-control(s) to p perform increment-p when other perform decrement-s evaluate true when s-result(r) = 'N' and s-repeat(r) = 0 *> no result perform increment-p when s-result(r) = 'N' and s-repeat(r) > 0 *> no result after success perform set-success perform increment-p when other *> fail the sequence perform increment-p end-evaluate end-evaluate
when p-symbol(p) = '(' *> start sequence perform increment-s perform display-start-control move p to s-start-control(s) move p-alternate(p) to s-alternate(s) move p-matching(p) to s-end-control(s) move 0 to s-count(s) perform increment-p
when p-symbol(p) = ')' *> end sequence perform display-end-control perform decrement-s evaluate true when s-result(r) = 'S' *> success perform set-success perform increment-p when s-result(r) = 'N' *> no result perform set-failure perform increment-p when other *> fail the sequence perform set-failure perform increment-p end-evaluate
when p-symbol(p) = '|' *> alternate evaluate true when s-result(s) = 'S' *> exit the sequence perform display-skip-alternate move s-end-control(s) to p when other perform display-take-alternate move p-alternate(p) to s-alternate(s) *> the next alternate perform increment-p perform set-nothing end-evaluate
when p-symbol(p) = 't' *> terminal move p-definition(p) to t move terminal-symbol-len(t) to t-len perform display-terminal evaluate true when statement(l:t-len) = terminal-symbol(t)(1:t-len) *> successful match perform set-success perform display-recognize-terminal perform process-token move t-len to l-len perform increment-l perform increment-p when s-alternate(s) <> 000 *> we are in an alternate sequence move s-alternate(s) to p when other *> fail the sequence perform set-failure move s-end-control(s) to p end-evaluate
when other *> end control perform display-control-failure *> shouldnt happen
end-evaluate
end-perform
evaluate true *> at end of evaluation when error-found = 'y' continue when l <= l-lim *> not all tokens parsed display 'error: invalid statement' perform statement-error when number-use <> spaces display 'error: not all numbers were used: ' number-use move 'y' to error-found end-evaluate .
increment-l.
evaluate true when l > l-lim *> end of statement continue when other add l-len to l perform varying l from l by 1 until c(l) <> space or l > l-lim continue end-perform move 1 to l-len if l > l-lim perform end-tokens end-if end-evaluate .
increment-p.
evaluate true when p >= p-max display 'at' space p ' parse overflow' space 's=<' s space s-entry(s) '>' move 'y' to error-found when other add 1 to p perform display-statement end-evaluate .
increment-s.
evaluate true when s >= s-max display 'at' space p ' stack overflow ' space 's=<' s space s-entry(s) '>' move 'y' to error-found when other move s to r add 1 to s initialize s-entry(s) move 'N' to s-result(s) move p to s-p(s) move nt to s-nt(s) end-evaluate .
decrement-s.
if s > 0 move s to r subtract 1 from s if s > 0 move s-nt(s) to nt end-if end-if .
set-failure.
move 'F' to s-result(s) if s-count(s) > 0 display 'sequential parse failure' perform statement-error end-if .
set-success.
move 'S' to s-result(s) add 1 to s-count(s) .
set-nothing.
move 'N' to s-result(s) move 0 to s-count(s) .
statement-error.
display statement move spaces to statement move '^ syntax error' to statement(l:) display statement move 'y' to error-found .
- >=====================
- > twentyfour semantics
- >=====================
test-variable.
*> check validity perform varying nd from 1 by 1 until nd > 4 or c(l) = n(nd) continue end-perform *> check usage perform varying nu from 1 by 1 until nu > 4 or c(l) = u(nu) continue end-perform evaluate true when l > l-lim perform set-failure when c9(l) not numeric perform set-failure when nd > 4 display 'invalid number' perform statement-error when nu > 4 display 'number already used' perform statement-error when other move space to u(nu) perform set-success add 1 to oqx move c(l) to output-queue(oqx:1) end-evaluate .
- > ==================================
- > Dijkstra Shunting-Yard Algorithm
- > to convert infix to rpn
- > ==================================
process-token.
evaluate true when c(l) = '(' add 1 to osx move c(l) to operator-stack(osx:1) when c(l) = ')' perform varying osx from osx by -1 until osx < 1 or operator-stack(osx:1) = '(' add 1 to oqx move operator-stack(osx:1) to output-queue(oqx:1) end-perform if osx < 1 display 'parenthesis error' perform statement-error exit paragraph end-if subtract 1 from osx when (c(l) = '+' or '-') and (operator-stack(osx:1) = '*' or '/') *> lesser operator precedence add 1 to oqx move operator-stack(osx:1) to output-queue(oqx:1) move c(l) to operator-stack(osx:1) when other *> greater operator precedence add 1 to osx move c(l) to operator-stack(osx:1) end-evaluate .
end-tokens.
*> 1) copy stacked operators to the output-queue perform varying osx from osx by -1 until osx < 1 or operator-stack(osx:1) = '(' add 1 to oqx move operator-stack(osx:1) to output-queue(oqx:1) end-perform if osx > 0 display 'parenthesis error' perform statement-error exit paragraph end-if *> 2) evaluate the rpn statement perform evaluate-rpn if divide-by-zero-error = 'y' display 'divide by zero error' end-if .
evaluate-rpn.
move space to divide-by-zero-error move 0 to rsx *> stack depth perform varying oqx1 from 1 by 1 until oqx1 > oqx if output-queue(oqx1:1) >= '1' and <= '9' *> push current data onto the stack add 1 to rsx move top-numerator to numerator(rsx) move top-denominator to denominator(rsx) move output-queue(oqx1:1) to top-numerator move 1 to top-denominator else *> apply the operation evaluate true when output-queue(oqx1:1) = '+' compute top-numerator = top-numerator * denominator(rsx) + top-denominator * numerator(rsx) compute top-denominator = top-denominator * denominator(rsx) when output-queue(oqx1:1) = '-' compute top-numerator = top-denominator * numerator(rsx) - top-numerator * denominator(rsx) compute top-denominator = top-denominator * denominator(rsx) when output-queue(oqx1:1) = '*' compute top-numerator = top-numerator * numerator(rsx) compute top-denominator = top-denominator * denominator(rsx) when output-queue(oqx1:1) = '/' compute work-number = numerator(rsx) * top-denominator compute top-denominator = denominator(rsx) * top-numerator if top-denominator = 0 move 'y' to divide-by-zero-error exit paragraph end-if move work-number to top-numerator end-evaluate *> pop the stack subtract 1 from rsx end-if end-perform .
- >====================
- > diagnostic displays
- >====================
display-start-nonterminal.
perform varying nt from nt-lim by -1 until nt < 1 or p-definition(p) = nonterminal-statement-number(nt) continue end-perform if nt > 0 move '1' to NL-flag string '1' indent(1:s + s) 'at ' s space p ' start ' trim(nonterminal-statement(nt)) into message-area perform display-message move nt to s-nt(s) end-if .
display-continue-nonterminal.
move s-nt(s) to nt string '1' indent(1:s + s) 'at ' s space p space p-symbol(p) ' continue ' trim(nonterminal-statement(nt)) ' with result ' s-result(s) into message-area perform display-message .
display-end-nonterminal.
move s-nt(s) to nt move '2' to NL-flag string '1' indent(1:s + s) 'at ' s space p ' end ' trim(nonterminal-statement(nt)) ' with result ' s-result(s) into message-area perform display-message .
display-start-control.
string '2' indent(1:s + s) 'at ' s space p ' start ' p-symbol(p) ' in ' trim(nonterminal-statement(nt)) into message-area perform display-message .
display-repeat-control.
string '2' indent(1:s + s) 'at ' s space p ' repeat ' p-symbol(p) ' in ' trim(nonterminal-statement(nt)) ' with result ' s-result(s) into message-area perform display-message .
display-end-control.
string '2' indent(1:s + s) 'at ' s space p ' end ' p-symbol(p) ' in ' trim(nonterminal-statement(nt)) ' with result ' s-result(s) into message-area perform display-message .
display-take-alternate.
string '2' indent(1:s + s) 'at ' s space p ' take alternate' ' in ' trim(nonterminal-statement(nt)) into message-area perform display-message .
display-skip-alternate.
string '2' indent(1:s + s) 'at ' s space p ' skip alternate' ' in ' trim(nonterminal-statement(nt)) into message-area perform display-message .
display-terminal.
string '1' indent(1:s + s) 'at ' s space p ' compare ' statement(l:t-len) ' to ' terminal-symbol(t)(1:t-len) ' in ' trim(nonterminal-statement(nt)) into message-area perform display-message .
display-recognize-terminal.
string '1' indent(1:s + s) 'at ' s space p ' recognize terminal: ' c(l) ' in ' trim(nonterminal-statement(nt)) into message-area perform display-message .
display-recognize-variable.
string '1' indent(1:s + s) 'at ' s space p ' recognize digit: ' c(l) ' in ' trim(nonterminal-statement(nt)) into message-area perform display-message .
display-statement.
compute p1 = p - s-start-control(s) string '3' indent(1:s + s) 'at ' s space p ' statement: ' s-start-control(s) '/' p1 space p-symbol(p) space s-result(s) ' in ' trim(nonterminal-statement(nt)) into message-area perform display-message .
display-control-failure.
display loop-count space indent(1:s + s) 'at' space p ' control failure' ' in ' trim(nonterminal-statement(nt)) display loop-count space indent(1:s + s) ' ' 'p=<' p p-entry(p) '>' display loop-count space indent(1:s + s) ' ' 's=<' s space s-entry(s) '>' display loop-count space indent(1:s + s) ' ' 'l=<' l space c(l)'>' perform statement-error .
display-message.
if display-level = 1 move space to NL-flag end-if evaluate true when loop-count > loop-lim *> loop control display 'display count exceeds ' loop-lim stop run when message-level <= display-level evaluate true when NL-flag = '1' display NL loop-count space trim(message-value) when NL-flag = '2' display loop-count space trim(message-value) NL when other display loop-count space trim(message-value) end-evaluate end-evaluate add 1 to loop-count move spaces to message-area move space to NL-flag .
end program twentyfour. </lang>
CoffeeScript
<lang coffeescript>tty = require 'tty' tty.setRawMode true
buffer = "" numbers = []
for n in [0...4]
numbers.push Math.max 1, Math.floor(Math.random() * 9)
console.log "You can use the numbers: #{numbers.join ' '}"
process.stdin.on 'keypress', (char, key) ->
# accept operator if char and isNaN(char) and /[()*\/+-]/.test(char) and buffer.substr(-1) isnt char buffer += char process.stdout.write char # accept number else if !isNaN(+char) and (buffer == or isNaN(buffer.substr -1)) buffer += char process.stdout.write char # check then evaluate expression if key?.name is 'enter' result = calculate() process.stdout.write '\n' if result and result is 24 console.log " = 24! congratulations." else console.log "#{result}. nope." process.exit 0 # quit if key?.name is 'escape' or (key?.name == 'c' and key.ctrl) process.exit 0
calculate = () ->
if /[^\d\s()+*\/-]/.test buffer console.log "invalid characters" process.exit 1 used = buffer.match(/\d/g) if used?.length != 4 or used.sort().join() != numbers.sort().join() console.log "you must use the 4 numbers provided" process.exit 1 res = try eval buffer catch e return res or 'invalid expression'
- begin taking input
process.stdin.resume() </lang>
Commodore BASIC
This solution was taken from the ZX Spectrum example further down, however, BASIC on the Spectrum features slightly different string handling functions. Most importantly, while the val()
function on the Spectrum is able to parse complete mathematical expressions with in a string while converting it to a number, Commodore BASIC will only obtain a single number provided the first character is a valid numeric character and up to any non-numeric character. (Even floating-point numbers where 0 < n < 1 must begin with a leading 0 prior to the decimal point.)
To get around this, this program utilizes BASIC's ability to parse expressions with the simple mathematical operators, and is in fact technically a self-modifying program. Line 2005 is a line padded with colons which simply allow BASIC to join multiple statements on a single line, otherwise perform no operation. This reserves sufficient space in memory for inserting the user's expression—by overwriting the first several bytes of colons—which can then be evaluated in the normal course of the program's execution. The subroutine at 1400 initializes a simple translation table for exchanging the operators into their proper BASIC tokens. Parenthesis, numerals, and variable names do not need to be translated.
After the user types in an expression, the program validates the input (same algorithms as the ZX Spectrum example), writes the expression as R=expression
as tokenized BASIC into line 2005, and then executes the subroutine at 2000 to obtain the value. Upon return, the normal evaluation of whether 24 was obtain is checked.
If the statement at line 645 is uncommented, this will allow the program to "erase" line 2005 and thus "hide" the trick. As is, if you list the program after making an attempt, you will see the last expression given to the program.
Since Commodore BASIC v2 was the initial target for this program, all other versions of Commodore BASIC are compatible as long as the base memory address for BASIC programs is adjusted. (BASIC tokens maintain compatibility across all versions.) Simply use the appropriate values for bh
and bl
in lines 11-15.
<lang gwbasic>1 rem 24 game 2 rem for rosetta code 10 rem use appropriate basic base address 11 bh=08:bl=01: rem $0801 commodore 64 12 rem bh=16:bl=01: rem $1001 commodore +4 13 rem bh=18:bl=01: rem $1201 commodore vic-20 (35k ram) 14 rem bh=04:bl=01: rem $0401 commodore pet 15 rem bh=28:bl=01: rem $1c01 commodore 128 (bank 0)
35 print chr$(147);chr$(14);"Initializing...":gosub 1400 40 n$="":x=rnd(-ti):rem similar to 'randomize' 45 for i=1 to 4 50 t$=str$(int(rnd(1)*9)+1) 55 n$=n$+mid$(t$,2,1) 60 next i
65 print chr$(147) 70 print spc(16);"24 Game" 71 print:print " The goal of this game is to formulate" 72 print:print " an arithmetic expression that" 73 print:print " evaluates to a value of 24, however" 74 print:print " you may only use four numbers provided" 75 print:print " at random by the computer and the" 76 print:print " standard arithmetic operations of add," 77 print:print " subtract, multiply, and divide. Each" 78 print:print " digit must be used by itself. (e.g. if" 79 print:print " given 1, 2, 3, 4, you cannot combine" 80 print:print " 1 and 2 to make 12.)" 89 gosub 1000
90 i$="":f$="":p$="" 95 print chr$(147);"Allowed characters:" 100 i$=n$+"+-*/()" 110 print 120 for i=1 to len(i$) 130 print mid$(i$,i,1);" "; 140 next i:print 150 print:print "Spaces are ignored." 155 print "Enter 'end' to end.":print 160 input "Enter the formula";f$ 170 if f$="end" then print "Program terminated.":end
180 print:print "Checking syntax... ";tab(34); 190 for i=1 to len(f$) 200 if mid$(f$,i,1)=" " then next i 210 c$=mid$(f$,i,1) 220 if c$="+" or c$="-" or c$="*" or c$="/" then p$=p$+"o":goto 250 230 if c$="(" or c$=")" then p$=p$+c$:goto 250 240 p$=p$+"n" 250 next i 260 restore 270 for i=1 to 11 280 read t$ 290 if t$=p$ then i=11 300 next i 310 if t$<>p$ then gosub 1100:gosub 1000:goto 90
315 print "OK":print "Checking for illegal numbers... ";tab(34); 320 for i=1 to len(f$) 330 for j=1 to 10 335 ft$=mid$(f$,i,1) 336 il$=left$(i$,j-1):it$=mid$(i$,j,1):ir$=mid$(i$,j+1,len(i$)) 340 if ft$=it$ and ft$>"0" and ft$<="9" then i$=il$+" "+ir$ 350 next j 360 next i 370 if mid$(i$,1,4)<>" " then gosub 1200:gosub 1000:goto 90
375 print "OK":print "Evaluating expression...":print:print tab(10);f$;" ="; 380 gosub 600:rem r=val(f$) 390 print r;" " 400 if r<>24 then gosub 1300:gosub 1000:goto 90 410 print "Correct!"
420 print:print "Would you like to go again (y/n)? "; 425 get k$:if k$<>"y" and k$<>"n" then 425 430 print k$ 435 if k$="y" then goto 10 440 print:print "Very well. Have a nice day!" 450 end
500 rem pattern matching 501 data "nononon","(non)onon","nono(non)" 504 data "no(no(non))","((non)on)on","no(non)on" 507 data "(non)o(non)","no((non)on)","(nonon)on" 510 data "(no(non))on","no(nonon)"
600 rem get basic to evaluate our expression 605 a$="r="+f$ 610 for i=1 to len(a$) 615 rem simple token translation 620 b=asc(mid$(a$,i,1)) 625 if (b>41 and b<48) or b=61 or b=94 then b=t(b) 630 poke (ad+i-1),b 635 next 640 gosub 2000 645 rem gosub 1440:rem uncomment to clear evaluation line after use 650 return
1000 rem screen pause 1005 pt$=" Press a key to continue. " 1010 print:print spc(20-int(len(pt$)/2)); 1015 print chr$(18);pt$;chr$(146); 1020 get k$:if k$=""then 1020 1030 return
1100 rem syntax error 1105 print "ERROR":print 1110 print "Maybe something is out of place..." 1120 return
1200 rem invalid arguments 1205 print "ERROR":print 1210 print "?Invalid Arguments - " 1215 print "You used a number that is not allowed." 1220 return
1300 rem wrong formula 1305 print:print "Wrong answer. Try again." 1310 return
1400 dim t(94):t(43)=170:t(45)=171:t(42)=172:t(47)=173:t(61)=178:t(94)=174 1405 rem locate line 2005 in ram 1410 lh=bh:ll=bl:nh=0:nl=0 1415 ad=lh*256+ll 1420 lh=peek(ad+1):ll=peek(ad) 1425 nl=peek(ad+2):nh=peek(ad+3):n=nh*256+nl 1430 if n<>2005 then goto 1415 1435 ad=ad+4 1440 for j=ad to ad+73:poke j,asc(":"):next 1445 return
2000 rem put 74 colons on the next line 2005 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 2010 return </lang>
- Output:
Initializing... 24 Game The goal of this game is to formulate an arithmetic expression that evaluates to a value of 24, however you may only use four numbers provided at random by the computer and the standard arithmetic operations of add, subtract, multiply, and divide. Each digit must be used by itself. (e.g. if given 1, 2, 3, 4, you cannot combine 1 and 2 to make 12.) Press a key to continue. Allowed characters: 6 3 3 5 + - * / ( ) Spaces are ignored. Enter 'end' to end. Enter the formula? (6-3)*(3+5) Checking syntax... OK Checking for illegal numbers... OK Evaluating expression... (6-3)*(3+5) = 24 Correct! Would you like to go again (y/n)? n Very well. Have a nice day! ready. █
Common Lisp
<lang lisp>(define-condition choose-digits () ()) (define-condition bad-equation (error) ())
(defun 24-game ()
(let (chosen-digits) (labels ((prompt () (format t "Chosen digits: ~{~D~^, ~}~%~ Enter expression (or `bye' to quit, `!' to choose new digits): " chosen-digits) (read)) (lose () (error 'bad-equation)) (choose () (setf chosen-digits (loop repeat 4 collecting (1+ (random 9))))) (check (e) (typecase e ((eql bye) (return-from 24-game)) ((eql !) (signal 'choose-digits)) (atom (lose)) (cons (check-sub (car e) (check-sub (cdr e) chosen-digits)) e))) (check-sub (sub allowed-digits) (typecase sub ((member nil + - * /) allowed-digits) (integer (if (member sub allowed-digits) (remove sub allowed-digits :count 1) (lose))) (cons (check-sub (car sub) (check-sub (cdr sub) allowed-digits))) (t (lose)))) (win () (format t "You win.~%") (return-from 24-game))) (choose) (loop (handler-case (if (= 24 (eval (check (prompt)))) (win) (lose)) (error () (format t "Bad equation, try again.~%")) (choose-digits () (choose)))))))</lang>
Verbose Implementation
<lang lisp> (defconstant +ops+ '(* / + -))
(defun expr-numbers (e &optional acc)
"Return all the numbers in argument positions in the expression." (cond ((numberp e) (cons e acc)) ((consp e) (append (apply #'append (mapcar #'expr-numbers (cdr e))) acc))))
(defun expr-well-formed-p (e)
"Return non-nil if the given expression is well-formed." (cond ((numberp e) t) ((consp e) (and (member (car e) +ops+) (every #'expr-well-formed-p (cdr e)))) (t nil)))
(defun expr-valid-p (e available-digits)
"Return non-nil if the expression is well-formed and uses exactly
the digits specified."
(and (expr-well-formed-p e) (equalp (sort (copy-seq available-digits) #'<) (sort (expr-numbers e) #'<))))
(defun expr-get (&optional using)
(emit "Enter lisp form~@[ using the digit~P ~{~D~^ ~}~]: " (when using (length using)) using) (let (*read-eval*) (read)))
(defun digits ()
(sort (loop repeat 4 collect (1+ (random 9))) #'<))
(defun emit (fmt &rest args)
(format t "~&~?" fmt args))
(defun prompt (digits)
(emit "Using only these operators:~%~%~ ~2T~{~A~^ ~}~%~%~ And exactly these numbers \(no repetition\):~%~%~ ~2T~{~D~^ ~}~%~%~ ~A" +ops+ digits (secondary-prompt)))
(defun secondary-prompt ()
(fill-to 50 "Enter a lisp form which evaluates to ~ the integer 24, or \"!\" to get fresh ~ digits, or \"q\" to abort."))
(defun fill-to (n fmt &rest args)
"Poor-man's text filling mechanism." (loop with s = (format nil "~?" fmt args) for c across s and i from 0 and j = 0 then (1+ j) ; since-last-newline ctr
when (char= c #\Newline) do (setq j 0)
else when (and (not (zerop j)) (zerop (mod j n))) do (loop for k from i below (length s) when (char= #\Space (schar s k)) do (progn (setf (schar s k) #\Newline j 0) (loop-finish))) finally (return s)))
(defun 24-game ()
(loop with playing-p = t and initial-digits = (digits)
for attempts from 0 and digits = initial-digits then (digits)
while playing-p
do (loop for e = (expr-get (unless (zerop attempts) digits)) do (case e (! (loop-finish)) (Q (setq playing-p nil) (loop-finish)) (R (emit "Current digits: ~S" digits)) (t (if (expr-valid-p e digits) (let ((v (eval e))) (if (eql v 24) (progn (emit "~%~%---> A winner is you! <---~%~%") (setq playing-p nil) (loop-finish)) (emit "Sorry, the form you entered ~ computes to ~S, not 24.~%~%" v))) (emit "Sorry, the form you entered did not ~ compute.~%~%"))))) initially (prompt initial-digits)))</lang>
Example Usage:
CL-USER 97 > (24-game) Using only these operators: * / + - And exactly these numbers (no repetition): 3 7 7 9 Enter a lisp form which evaluates to the integer 24, or "!" to get fresh digits, or "q" to abort. Enter lisp form: (eval (read-from-string "(/ 1 0)")) Sorry, the form you entered did not compute. Enter lisp form: ! Enter lisp form using the digits 4 5 7 8: ! Enter lisp form using the digits 1 2 4 5: (* 4 (* 5 (- 2 1))) Sorry, the form you entered computes to 20, not 24. Enter lisp form using the digits 1 2 4 5: (* 4 (+ 5 (- 2 1))) ---> A winner is you! <--- NIL
D
<lang d>import std.stdio, std.random, std.math, std.algorithm, std.range,
std.typetuple;
void main() {
void op(char c)() { if (stack.length < 2) throw new Exception("Wrong expression."); stack[$ - 2] = mixin("stack[$ - 2]" ~ c ~ "stack[$ - 1]"); stack.popBack(); }
const problem = iota(4).map!(_ => uniform(1, 10))().array(); writeln("Make 24 with the digits: ", problem);
double[] stack; int[] digits; foreach (const char c; readln()) switch (c) { case ' ', '\t', '\n': break; case '1': .. case '9': stack ~= c - '0'; digits ~= c - '0'; break; foreach (o; TypeTuple!('+', '-', '*', '/')) { case o: op!o(); break; } break; default: throw new Exception("Wrong char: " ~ c); }
if (!digits.sort().equal(problem.dup.sort())) throw new Exception("Not using the given digits."); if (stack.length != 1) throw new Exception("Wrong expression."); writeln("Result: ", stack[0]); writeln(abs(stack[0] - 24) < 0.001 ? "Good job!" : "Try again.");
}</lang> Example:
Make 24 with the digits: [1, 8, 9, 8] 8 1 - 9 + 8 + Result: 24 Good job!
EchoLisp
<lang scheme> (string-delimiter "")
- check that nums are in expr, and only once
(define (is-valid? expr sorted: nums)
(when (equal? 'q expr) (error "24-game" "Thx for playing")) (unless (and (list? expr) (equal? nums (list-sort < (filter number? (flatten expr))))) (writeln "🎃 Please use" nums) #f))
- 4 random digits
(define (gen24)
(->> (append (range 1 10)(range 1 10)) shuffle (take 4) (list-sort < )))
(define (is-24? num)
(unless (= 24 num) (writeln "😧 Sorry - Result = " num) #f))
(define (check-24 expr)
(if (and (is-valid? expr nums) (is-24? (js-eval (string expr)))) ;; use js evaluator "🍀 🌸 Congrats - (play24) for another one." (input-expr check-24 (string nums))))
(define nums null) (define (play24)
(set! nums (gen24)) (writeln "24-game - Can you combine" nums "to get 24 ❓ (q to exit)") (input-expr check-24 (string-append (string nums) " -> 24 ❓")))
</lang>
- Output:
24-game - Can you combine (2 5 6 7) to get 24 ❓ (q to exit) difficult game 🎃 Please use (2 5 6 7) 12 * 2 🎃 Please use (2 5 6 7) 6 * (7 - 5 + 2) 🍀 🌸 Congrats - (play24) for another one. (play24) 24-game - Can you combine (3 5 8 9) to get 24 ❓ (q to exit) 3 + 5 + 8 * 9 😧 Sorry - Result = 80 9 * 3 - (8 - 5) 🍀 🌸 Congrats - (play24) for another one. (play24) 24-game - Can you combine (1 8 8 9) to get 24 ❓ (q to exit) 9 + 8 + 8 - 1 🍀 🌸 Congrats - (play24) for another one.
Elena
ELENA 5.0 : <lang elena>import system'routines; import system'collections; import system'dynamic; import extensions;
// --- Expression ---
class ExpressionTree {
object theTree; constructor(s) { auto level := new Integer(0); s.forEach:(ch) { var node := new DynamicStruct(); ch => $43 { node.Level := level + 1; node.Operation := __subj add } // + $45 { node.Level := level + 1; node.Operation := __subj subtract } // - $42 { node.Level := level + 2; node.Operation := __subj multiply } // * $47 { node.Level := level + 2; node.Operation := __subj divide } // / $40 { level.append(10); ^ self } // ( $41 { level.reduce(10); ^ self } // ) : { node.Leaf := ch.toString().toReal(); node.Level := level + 3 }; if (nil == theTree) { theTree := node } else { if (theTree.Level >= node.Level) { node.Left := theTree; node.Right := nilValue; theTree := node } else { var top := theTree; while ((nilValue != top.Right)&&(top.Right.Level < node.Level)) { top := top.Right }; node.Left := top.Right; node.Right := nilValue; top.Right := node } } } } eval(node) { if (node.containsProperty(subjconst Leaf)) { ^ node.Leaf } else { var left := self.eval(node.Left); var right := self.eval(node.Right); var op := node.Operation; ^ op(left, right); } } get Value() <= eval(theTree); readLeaves(list, node) { if (nil == node) { InvalidArgumentException.raise() }; if (node.containsProperty(subjconst Leaf)) { list.append(node.Leaf) } else { self.readLeaves(list, node.Left); self.readLeaves(list, node.Right) } } readLeaves(list) <= readLeaves(list,theTree);
}
// --- Game ---
class TwentyFourGame {
object theNumbers; constructor() { self.newPuzzle(); } newPuzzle() { theNumbers := new object[] { 1 + randomGenerator.eval:9, 1 + randomGenerator.eval:9, 1 + randomGenerator.eval:9, 1 + randomGenerator.eval:9 } } help() { console .printLine:"------------------------------- Instructions ------------------------------" .printLine:"Four digits will be displayed." .printLine:"Enter an equation using all of those four digits that evaluates to 24" .printLine:"Only * / + - operators and () are allowed" .printLine:"Digits can only be used once, but in any order you need." .printLine:"Digits cannot be combined - i.e.: 12 + 12 when given 1,2,2,1 is not allowed" .printLine:"Submit a blank line to skip the current puzzle." .printLine:"Type 'q' to quit" .writeLine() .printLine:"Example: given 2 3 8 2, answer should resemble 8*3-(2-2)" .printLine:"------------------------------- --------------------------------------------" } prompt() { theNumbers.forEach:(n){ console.print(n," ") }; console.print:": " } resolve(expr) { var tree := new ExpressionTree(expr); var leaves := new ArrayList(); tree.readLeaves:leaves; ifnot (leaves.ascendant().sequenceEqual(theNumbers.ascendant())) { console.printLine:"Invalid input. Enter an equation using all of those four digits. Try again."; ^ self }; var result := tree.Value; if (result == 24) { console.printLine("Good work. ",expr,"=",result); self.newPuzzle() } else { console.printLine("Incorrect. ",expr,"=",result) } }
}
extension gameOp {
playRound(expr) { if (expr == "q") { ^ false } else { if (expr == "") { console.printLine:"Skipping this puzzle"; self.newPuzzle() } else { try { self.resolve(expr) } catch(Exception e) { console.printLine:"An error occurred. Check your input and try again." } }; ^ true } }
}
public program() {
var game := new TwentyFourGame().help();
while (game.prompt().playRound(console.readLine())) {}
}</lang>
- Output:
------------------------------- Instructions ------------------------------ Four digits will be displayed. Enter an equation using all of those four digits that evaluates to 24 Only * / + - operators and () are allowed Digits can only be used once, but in any order you need. Digits cannot be combined - i.e.: 12 + 12 when given 1,2,2,1 is not allowed Submit a blank line to skip the current puzzle. Type 'q' to quit Example: given 2 3 8 2, answer should resemble 8*3-(2-2) ------------------------------- -------------------------------------------- 7 6 9 6 : Skipping this puzzle 8 6 2 6 : 6*6-8-2 Incorrect. 6*6-8-2=26.0 8 6 2 6 : Skipping this puzzle 5 2 7 7 : 7+7+(5*2) Good work. 7+7+(5*2)=24.0
Elixir
<lang elixir>defmodule Game24 do
def main do IO.puts "24 Game" play end defp play do IO.puts "Generating 4 digits..." digts = for _ <- 1..4, do: Enum.random(1..9) IO.puts "Your digits\t#{inspect digts, char_lists: :as_lists}" read_eval(digts) play end defp read_eval(digits) do exp = IO.gets("Your expression: ") |> String.strip if exp in ["","q"], do: exit(:normal) # give up case {correct_nums(exp, digits), eval(exp)} do {:ok, x} when x==24 -> IO.puts "You Win!" {:ok, x} -> IO.puts "You Lose with #{inspect x}!" {err, _} -> IO.puts "The following numbers are wrong: #{inspect err, char_lists: :as_lists}" end end defp correct_nums(exp, digits) do nums = String.replace(exp, ~r/\D/, " ") |> String.split |> Enum.map(&String.to_integer &1) if length(nums)==4 and (nums--digits)==[], do: :ok, else: nums end defp eval(exp) do try do Code.eval_string(exp) |> elem(0) rescue e -> Exception.message(e) end end
end
Game24.main</lang>
- Output:
24 Game Generating 4 digits... Your digits [9, 6, 7, 4] Your expression: (9+7)*6/4 You Win! Generating 4 digits... Your digits [3, 2, 2, 4] Your expression: 3*(2+2+4) You Win!
Erlang
<lang Erlang>-module(g24). -export([main/0]).
main() ->
random:seed(now()), io:format("24 Game~n"), play().
play() ->
io:format("Generating 4 digits...~n"), Digts = [random:uniform(X) || X <- [9,9,9,9]], io:format("Your digits\t~w~n", [Digts]), read_eval(Digts), play().
read_eval(Digits) ->
Exp = string:strip(io:get_line(standard_io, "Your expression: "), both, $\n), case {correct_nums(Exp, Digits), eval(Exp)} of {ok, X} when X == 24 -> io:format("You Win!~n"); {ok, X} -> io:format("You Lose with ~p!~n",[X]); {List, _} -> io:format("The following numbers are wrong: ~p~n", [List]) end.
correct_nums(Exp, Digits) ->
case re:run(Exp, "([0-9]+)", [global, {capture, all_but_first, list}]) of nomatch -> "No number entered"; {match, IntLs} -> case [X || [X] <- IntLs, not lists:member(list_to_integer(X), Digits)] of [] -> ok; L -> L end end.
eval(Exp) ->
{X, _} = eval(re:replace(Exp, "\\s", "", [{return, list},global]), 0), X.
eval([], Val) ->
{Val,[]};
eval([$(|Rest], Val) ->
{NewVal, Exp} = eval(Rest, Val), eval(Exp, NewVal);
eval([$)|Rest], Val) ->
{Val, Rest};
eval([$[|Rest], Val) ->
{NewVal, Exp} = eval(Rest, Val), eval(Exp, NewVal);
eval([$]|Rest], Val) ->
{Val, Rest};
eval([$+|Rest], Val) ->
{NewOperand, Exp} = eval(Rest, 0), eval(Exp, Val + NewOperand);
eval([$-|Rest], Val) ->
{NewOperand, Exp} = eval(Rest, 0), eval(Exp, Val - NewOperand);
eval([$*|Rest], Val) ->
{NewOperand, Exp} = eval(Rest, 0), eval(Exp, Val * NewOperand);
eval([$/|Rest], Val) ->
{NewOperand, Exp} = eval(Rest, 0), eval(Exp, Val / NewOperand);
eval([X|Rest], 0) when X >= $1, X =< $9 ->
eval(Rest, X-$0).
</lang>
The evaluator uses a simple infix scheme that doesn't care about operator precedence, but does support brackets and parentheses alike. Thus, ((9+1)*2)+2+2
is evaluated as:
9 + 1 = 10 10 * 2 = 20 2 + 2 = 4 20 + 4
Example:
1> c(g24). {ok,g24} 2> g24:main(). 24 Game Generating 4 digits... Your digits [7,4,6,8] Your expression: 6*4 You Win! Generating 4 digits... Your digits [4,1,5,8] Your expression: 6*4 The following numbers are wrong: ["6"] Generating 4 digits... Your digits [8,5,8,2] Your expression: 2*([8/5]*2) You Lose with 6.4! Generating 4 digits... Your digits [7,4,8,1]
F#
<lang fsharp>open System open System.Text.RegularExpressions
// Some utilities let (|Parse|_|) regex str =
let m = Regex(regex).Match(str) if m.Success then Some ([for g in m.Groups -> g.Value]) else None
let rec gcd x y = if x = y || x = 0 then y else if x < y then gcd y x else gcd y (x-y) let abs (x : int) = Math.Abs x let sign (x: int) = Math.Sign x let cint s = Int32.Parse(s) let replace m (s : string) t = Regex.Replace(t, m, s)
// computing in Rationals type Rat(x : int, y : int) =
let g = if y <> 0 then gcd (abs x) (abs y) else raise <| DivideByZeroException() member this.n = sign y * x / g // store a minus sign in the numerator member this.d = if y <> 0 then sign y * y / g else raise <| DivideByZeroException() static member (~-) (x : Rat) = Rat(-x.n, x.d) static member (+) (x : Rat, y : Rat) = Rat(x.n * y.d + y.n * x.d, x.d * y.d) static member (-) (x : Rat, y : Rat) = x + Rat(-y.n, y.d) static member (*) (x : Rat, y : Rat) = Rat(x.n * y.n, x.d * y.d) static member (/) (x : Rat, y : Rat) = x * Rat(y.d, y.n) override this.ToString() = sprintf @"<%d,%d>" this.n this.d new(x : string, y : string) = if y = "" then Rat(cint x, 1) else Rat(cint x, cint y)
// Due to the constraints imposed by the game (reduced set // of operators, all left associativ) we can get away with a repeated reduction // to evaluate the algebraic expression. let rec reduce (str :string) =
let eval (x : Rat) (y : Rat) = function | "*" -> x * y | "/" -> x / y | "+" -> x + y | "-" -> x - y | _ -> failwith "unknown op" let subst s r = str.Replace(s, r.ToString()) let rstr = match str with | Parse @"\(<(-?\d+),(\d+)>([*/+-])<(-?\d+),(\d+)>\)" [matched; xn; xd; op; yn; yd] -> subst matched <| eval (Rat(xn,xd)) (Rat(yn,yd)) op | Parse @"<(-?\d+),(\d+)>([*/])<(-?\d+),(\d+)>" [matched; xn; xd; op; yn; yd] -> subst matched <| eval (Rat(xn,xd)) (Rat(yn,yd)) op | Parse @"<(-?\d+),(\d+)>([+-])<(-?\d+),(\d+)>" [matched; xn; xd; op; yn; yd] -> subst matched <| eval (Rat(xn,xd)) (Rat(yn,yd)) op | Parse @"\(<(-?\d+),(\d+)>\)" [matched; xn; xd] -> subst matched <| Rat(xn,xd) | Parse @"(?<!>)-<(-?\d+),(\d+)>" [matched; xn; xd] -> subst matched <| -Rat(xn,xd) | _ -> str if str = rstr then str else reduce rstr
let gameLoop() =
let checkInput dddd input = match input with | "n" | "q" -> Some(input) | Parse @"[^1-9()*/+-]" [c] -> printfn "You used an illegal character in your expression: %s" c None | Parse @"^\D*(\d)\D+(\d)\D+(\d)\D+(\d)(?:\D*(\d))*\D*$" [m; d1; d2; d3; d4; d5] -> if d5 = "" && (String.Join(" ", Array.sort [|d1;d2;d3;d4|])) = dddd then Some(input) elif d5 = "" then printfn "Use this 4 digits with operators in between: %s." dddd None else printfn "Use only this 4 digits with operators in between: %s." dddd None | _ -> printfn "Use all 4 digits with operators in between: %s." dddd None let rec userLoop dddd = let tryAgain msg = printfn "%s" msg userLoop dddd printf "[Expr|n|q]: " match Console.ReadLine() |> replace @"\s" "" |> checkInput dddd with | Some(input) -> let data = input |> replace @"((?<!\d)-)?\d+" @"<$&,1>" match data with | "n" -> true | "q" -> false | _ -> try match reduce data with | Parse @"^<(-?\d+),(\d+)>$" [_; x; y] -> let n, d = (cint x), (cint y) if n = 24 then printfn "Correct!" true elif d=1 then tryAgain <| sprintf "Wrong! Value = %d." n else tryAgain <| sprintf "Wrong! Value = %d/%d." n d | _ -> tryAgain "Wrong! not a well-formed expression!" with | :? System.DivideByZeroException -> tryAgain "Wrong! Your expression results in a division by zero!" | ex -> tryAgain <| sprintf "There is an unforeseen problem with yout input: %s" ex.Message | None -> userLoop dddd
let random = new Random(DateTime.Now.Millisecond) let rec loop() = let dddd = String.Join(" ", Array.init 4 (fun _ -> 1 + random.Next 9) |> Array.sort) printfn "\nCompute 24 from the following 4 numbers: %s" dddd printfn "Use them in any order with * / + - and parentheses; n = new numbers; q = quit" if userLoop dddd then loop()
loop()
gameLoop()</lang>
- Output:
Compute 24 from the following 4 numbers: 3 3 3 5 Use them in any order with * / + - and parentheses; n = new numbers; q = quit [Expr|n|q]: n Compute 24 from the following 4 numbers: 3 5 6 7 Use them in any order with * / + - and parentheses; n = new numbers; q = quit [Expr|n|q]: (7 + 5) + 6/3 Wrong! Value = 14. [Expr|n|q]: (7 + 5) * 6/3 Correct! Compute 24 from the following 4 numbers: 3 3 4 5 Use them in any order with * / + - and parentheses; n = new numbers; q = quit [Expr|n|q]: q
Factor
<lang factor>USING:
combinators.short-circuit continuations eval formatting fry kernel io math math.ranges prettyprint random sequences sets ;
IN: 24game
- choose4 ( -- seq )
4 [ 9 [1,b] random ] replicate ;
- step ( numbers -- ? )
readln [ parse-string { ! Is only allowed tokens used? [ swap { + - / * } append subset? ] ! Digit count in expression should be equal to the given numbers. [ [ number? ] count swap length = ] ! Of course it must evaluate to 24 [ nip call( -- x ) 24 = ] } 2&& [ f "You got it!" ] [ t "Expression isnt valid, or doesnt evaluate to 24." ] if ] [ 3drop f "Could not parse that." ] recover print flush ;
- main ( -- )
choose4 [ "Your numbers are %[%s, %], make an expression\n" printf flush ] [ '[ _ step ] loop ] bi ;
</lang> Sample: <lang factor> IN: scratchpad main Your numbers are { 4, 1, 8, 2 }, make an expression 8 4 + 2 * 1 / You got it! </lang>
Falcon
<lang falcon>load compiler
function genRandomNumbers( amount )
rtn = [] for i in [ 0 : amount ]: rtn += random( 1, 9 ) return( rtn )
end
function getAnswer( exp )
ic = ICompiler() ic.compileAll(exp)
return( ic.result )
end
function validInput( str )
for i in [ 0 : str.len() ] if str[i] notin ' ()[]0123456789-+/*' > 'INVALID Character = ', str[i] return( false ) end end
return( true )
end
printl(' The 24 Game
Given any four digits in the range 1 to 9, which may have repetitions, Using just the +, -, *, and / operators; and the possible use of brackets, (), show how to make an answer of 24.
An answer of "q" will quit the game. An answer of "!" will generate a new set of four digits. Otherwise you are repeatedly asked for an expression until it evaluates to 24
Note: you cannot form multiple digit numbers from the supplied digits, so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed. ')
num = genRandomNumbers( 4 )
while( true )
>> "Here are the numbers to choose from: " map({ a => print(a, " ") }, num) >
exp = input()
switch exp case "q", "Q" exit()
case "!" > 'Generating new numbers list' num = genRandomNumbers( 4 )
default if not validInput( exp ): continue
answer = getAnswer( exp )
if answer == 24 > "By George you GOT IT! Your expression equals 24" else > "Ahh Sorry, So Sorry your answer of ", answer, " does not equal 24." end end
end</lang>
Fortran
Clever implementation
Indicate operator precedence by parentheses; e.g. (3+(5*6))-9. No whitespace is admissible. The program uses Insertion_sort in Fortran. <lang Fortran>program game_24
implicit none real :: vector(4), reals(11), result, a, b, c, d integer :: numbers(4), ascii(11), i character(len=11) :: expression character :: syntax(11) ! patterns: character, parameter :: one(11) = (/ '(','(','1','x','1',')','x','1',')','x','1' /) character, parameter :: two(11) = (/ '(','1','x','(','1','x','1',')',')','x','1' /) character, parameter :: three(11) = (/ '1','x','(','(','1','x','1',')','x','1',')' /) character, parameter :: four(11) = (/ '1','x','(','1','x','(','1','x','1',')',')' /) character, parameter :: five(11) = (/ '(','1','x','1',')','x','(','1','x','1',')' /) do call random_number(vector) numbers = 9 * vector + 1 write (*,*) 'Digits: ',numbers write (*,'(a)',advance='no') 'Your expression: ' read (*,'(a11)') expression
forall (i=1:11) syntax(i) = expression(i:i) ascii = iachar(syntax) where (syntax >= '0' .and. syntax <= '9') syntax = '1' ! number elsewhere (syntax == '+' .or. syntax == '-' .or. syntax == '*' .or. syntax == '/') syntax = 'x' ! op elsewhere (syntax /= '(' .and. syntax /= ')') syntax = '-' ! error end where
reals = real(ascii-48) if ( all(syntax == one) ) then a = reals(3); b = reals(5); c = reals(8); d = reals(11) call check_numbers(a,b,c,d) result = op(op(op(a,4,b),7,c),10,d) else if ( all(syntax == two) ) then a = reals(2); b = reals(5); c = reals(7); d = reals(11) call check_numbers(a,b,c,d) result = op(op(a,3,op(b,6,c)),10,d) else if ( all(syntax == three) ) then a = reals(1); b = reals(5); c = reals(7); d = reals(10) call check_numbers(a,b,c,d) result = op(a,2,op(op(b,6,c),9,d)) else if ( all(syntax == four) ) then a = reals(1); b = reals(4); c = reals(7); d = reals(9) call check_numbers(a,b,c,d) result = op(a,2,op(b,5,op(c,8,d))) else if ( all(syntax == five) ) then a = reals(2); b = reals(4); c = reals(8); d = reals(10) call check_numbers(a,b,c,d) result = op(op(a,3,b),6,op(c,9,d)) else stop 'Input string: incorrect syntax.' end if
if ( abs(result-24.0) < epsilon(1.0) ) then write (*,*) 'You won!' else write (*,*) 'Your result (',result,') is incorrect!' end if write (*,'(a)',advance='no') 'Another one? [y/n] ' read (*,'(a1)') expression if ( expression(1:1) == 'n' .or. expression(1:1) == 'N' ) then stop end if end do
contains
pure real function op(x,c,y) integer, intent(in) :: c real, intent(in) :: x,y select case ( char(ascii(c)) ) case ('+') op = x+y case ('-') op = x-y case ('*') op = x*y case ('/') op = x/y end select end function op subroutine check_numbers(a,b,c,d) real, intent(in) :: a,b,c,d integer :: test(4) test = (/ nint(a),nint(b),nint(c),nint(d) /) call Insertion_Sort(numbers) call Insertion_Sort(test) if ( any(test /= numbers) ) then stop 'You cheat ;-) (Incorrect numbers)' end if end subroutine check_numbers pure subroutine Insertion_Sort(a) integer, intent(inout) :: a(:) integer :: temp, i, j do i=2,size(a) j = i-1 temp = a(i) do while ( j>=1 .and. a(j)>temp ) a(j+1) = a(j) j = j - 1 end do a(j+1) = temp end do end subroutine Insertion_Sort
end program game_24 </lang>
As a more general recursive descent parser:
Permits spaces and arbitrary parentheses.
<lang FORTRAN> ! implement a recursive descent parser module evaluate_algebraic_expression
integer, parameter :: size = 124 character, parameter :: statement_end = achar(0) character(len=size) :: text_to_parse integer :: position data position/0/,text_to_parse/' '/
contains
character function get_token() ! return the current token implicit none if (position <= size) then get_token = text_to_parse(position:position) do while (get_token <= ' ') call advance if (size < position) exit get_token = text_to_parse(position:position) end do end if if (size < position) get_token = statement_end end function get_token
subroutine advance ! consume a token. Move to the next token. consume_token would have been a better name. position = position + 1 end subroutine advance logical function unfinished() unfinished = get_token() /= statement_end end function unfinished
subroutine parse_error() write(6,*)'"'//get_token()//'" unexpected in expression at',position stop 1 end subroutine parse_error
function precedence3() result(a) implicit none real :: a character :: token character(len=10), parameter :: digits = '0123456789' token = get_token() if (verify(token,digits) /= 0) call parse_error() a = index(digits, token) - 1 call advance() end function precedence3
recursive function precedence2() result(a) real :: a character :: token token = get_token() if (token /= '(') then a = precedence3() else call advance a = precedence0() token = get_token() if (token /= ')') call parse_error() call advance end if end function precedence2
recursive function precedence1() result(a) implicit none real :: a real, dimension(2) :: argument character(len=2), parameter :: tokens = '*/' character :: token a = 0 token = get_token() argument(1) = precedence2() token = get_token() do while (verify(token,tokens) == 0) call advance() argument(2) = precedence2() if (token == '/') argument(2) = 1 / argument(2) argument(1) = product(argument) token = get_token() end do a = argument(1) end function precedence1
recursive function precedence0() result(a) implicit none real :: a real, dimension(2) :: argument character(len=2), parameter :: tokens = '+-' character :: token a = 0 token = get_token() argument(1) = precedence1() token = get_token() do while (verify(token,tokens) == 0) call advance() argument(2) = precedence1() if (token == '-') argument = argument * (/1, -1/) argument(1) = sum(argument) token = get_token() end do a = argument(1) end function precedence0
real function statement() implicit none if (unfinished()) then statement = precedence0() else !empty okay statement = 0 end if if (unfinished()) call parse_error() end function statement
real function evaluate(expression) implicit none character(len=*), intent(in) :: expression text_to_parse = expression evaluate = statement() end function evaluate
end module evaluate_algebraic_expression
program g24
use evaluate_algebraic_expression implicit none integer, dimension(4) :: digits character(len=78) :: expression real :: result ! integer :: i call random_seed!easily found internet examples exist to seed by /dev/urandom or time call deal(digits) ! do i=1, 9999 ! produce the data to test digit distribution ! call deal(digits) ! write(6,*) digits ! end do write(6,'(a13,4i2,a26)')'Using digits',digits,', and the algebraic dyadic' write(6,*)'operators +-*/() enter an expression computing 24.' expression = ' ' read(5,'(a78)') expression if (invalid_digits(expression, digits)) then write(6,*)'invalid digits' else result = evaluate(expression) if (nint(result) == 24) then write(6,*) result, ' close enough' else write(6,*) result, ' no good' end if end if
contains
logical function invalid_digits(e,d) !verify the digits implicit none character(len=*), intent(in) :: e integer, dimension(4), intent(inout) :: d integer :: i, j, k, count logical :: unfound count = 0 invalid_digits = .false. !validity assumed !write(6,*)'expression:',e(1:len_trim(e)) do i=1, len_trim(e) if (verify(e(i:i),'0123456789') == 0) then j = index('0123456789',e(i:i))-1 unfound = .true. do k=1, 4 if (j == d(k)) then unfound = .false. exit end if end do if (unfound) then invalid_digits = .true. !return or exit is okay here else d(k) = -99 count = count + 1 end if end if end do invalid_digits = invalid_digits .or. (count /= 4) end function invalid_digits
subroutine deal(digits) implicit none integer, dimension(4), intent(out) :: digits integer :: i real :: harvest call random_number(harvest) do i=1, 4 digits(i) = int(mod(harvest*9**i, 9.0)) + 1 end do ! NB. computed with executable Iverson notation, www.jsoftware.oom ! #B NB. B are the digits from 9999 deals ! 39996 ! ({.,#)/.~/:~B # show the distribution of digits ! 0 4380 ! 1 4542 ! 2 4348 ! 3 4395 ! 4 4451 ! 5 4474 ! 6 4467 ! 7 4413 ! 8 4526 ! NB. this also shows that I forgot to add 1. Inserting now... end subroutine deal
end program g24 </lang>
Compilation and too many examples. Which would you cut?
$ gfortran -g -O0 -std=f2008 -Wall f.f08 -o f.exe && echo '8*(9/9+2)' | ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. 24.000000 close enough $ $ $ $ ./f.exe $ Using digits 9 9 8 2, and the algebraic dyadic $ operators +-*/() enter an expression computing 24. $ 8 * ( 9 / 9 + 2 ) $ 24.000000 close enough $ $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. (((2+8+9+9))) 28.000000 no good $ $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. (((8+9-2+9))) 24.000000 close enough $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. 8929 "9" unexpected in expression at 2 STOP 1 $ $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. 12348 invalid digits $ $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. 892 invalid digits $ $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. 8921 invalid digits $ $ $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. 89291 invalid digits $ $ $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. 9+x-2+8+9 "x" unexpected in expression at 3 STOP 1 $ $ $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. (9-2)+8+(9 "^@" unexpected in expression at 125 STOP 1 $ $ $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. (9-2)+8+(9) 24.000000 close enough $ $ $ $ ./f.exe Using digits 9 9 8 2, and the algebraic dyadic operators +-*/() enter an expression computing 24. (9-2)+8/(9) 7.8888888 no good $
FreeBASIC
Solución en RPN: <lang freebasic> ' The 24 game en FreeBASIC
Const operaciones = "*/+-"
Declare Sub Encabezado Declare Function escoge4() As String Declare Function quitaEspacios(cadena As String, subcadena1 As String, subcadena2 As String) As String Declare Function evaluaEntrada(cadena As String) As Integer Declare Function evaluador(oper1 As Byte, oper2 As Byte, operacion As String) As Integer
Dim Shared As String serie, entrada, cadena Dim As Integer resultado
Sub Encabezado
Cls: Color 15 Print "The 24 Game" Print "============" + Chr(13) + Chr(10) Print "Dados cuatro dígitos en el rango de 1 a 9, que pueden repetirse, " Print "usando solo los operadores aritméticos suma (+), resta (-), " Print "multiplicación (*) y división (/) intentar obtener un resultado de 24." + Chr(13) + Chr(10) Print "Use la notación polaca inversa (primero los operandos y luego los operadores)." Print "Por ejemplo: en lugar de 2 + 4, escriba 2 4 +" + Chr(13) + Chr(10)
End Sub
Function escoge4() As String
Dim As Byte i Dim As String a, b Print "Los dígitos a utilizar son: "; For i = 1 To 4
a = Str(Int(Rnd*9)+1) Print a;" "; b = b + a
Next i escoge4 = b
End Function
Function evaluaEntrada(cadena As String) As Integer
Dim As Byte oper1, oper2, n(4), i Dim As String op oper1 = 0: oper2 = 0: i = 0 While cadena <> ""
op = Left(cadena, 1) entrada = Mid(cadena, 2) If Instr(serie, op) Then i = i + 1 n(i) = Val(op)
Elseif Instr(operaciones, op) Then
oper2 = n(i) n(i) = 0 i = i - 1 oper1 = n(i) n(i) = evaluador(oper1, oper2, op)
Else
Print "Signo no v lido"
End If Wend evaluaEntrada = n(i)
End Function
Function evaluador(oper1 As Byte, oper2 As Byte, operacion As String) As Integer
Dim As Integer t Select Case operacion Case "+": t = oper1 + oper2 Case "-": t = oper1 - oper2 Case "*": t = oper1 * oper2 Case "/": t = oper1 / oper2 End Select evaluador = t
End Function
Function quitaEspacios(cadena As String, subcadena1 As String, subcadena2 As String) As String
Dim As Byte len1 = Len(subcadena1), len2 = Len(subcadena2) Dim As Byte i i = Instr(cadena, subcadena1) While i cadena = Left(cadena, i - 1) & subcadena2 & Mid(cadena, i + len1) i = Instr(i + len2, cadena, subcadena1) Wend quitaEspacios = cadena
End Function
'--- Programa Principal --- Randomize Timer Do
Encabezado serie = escoge4 Print: Line Input "Introduzca su fórmula en notación polaca inversa: ", entrada entrada = quitaEspacios(entrada, " ", "") If (Len(entrada) <> 7) Then Print "Error en la serie introducida." Else resultado = evaluaEntrada(entrada) Print "El resultado es = "; resultado If resultado = 24 Then Print "¡Correcto!" Else Print "¡Error!" End If End If Print "¿Otra ronda? (Pulsa S para salir, u otra tecla para continuar)"
Loop Until (Ucase(Input(1)) = "S") End '-------------------------- </lang>
- Output:
The 24 Game ============ Dados cuatro dígitos en el rango de 1 a 9, que pueden repetirse, usando solo los operadores aritmÚticos suma (+), resta (-), multiplicación (*) y división (/) intentar obtener un resultado de 24. Use la notación polaca inversa (primero los operandos y luego los operadores). Por ejemplo: en lugar de 2 + 4, escriba 2 4 + Los dígitos a utilizar son: 4 9 7 5 Introduzca su fórmula en notación polaca inversa: 49*57+- El resultado es = 24 Correcto! ¿Otra ronda? (Pulsa S para salir, u otra tecla para continuar)
GAP
Solution in RPN: <lang gap>Play24 := function() local input, digits, line, c, chars, stack, stackptr, cur, p, q, ok, a, b, run; input := InputTextUser(); run := true; while run do digits := List([1 .. 4], n -> Random(1, 9)); while true do Display(digits); line := ReadLine(input); line := Chomp(line); if line = "end" then run := false; break; elif line = "next" then break; else ok := true; stack := [ ]; stackptr := 0; chars := "123456789+-*/ "; cur := ShallowCopy(digits); for c in line do if c = ' ' then continue; fi; p := Position(chars, c); if p = fail then ok := false; break; fi; if p < 10 then q := Position(cur, p); if q = fail then ok := false; break; fi; Unbind(cur[q]); stackptr := stackptr + 1; stack[stackptr] := p; else if stackptr < 2 then ok := false; break; fi; b := stack[stackptr]; a := stack[stackptr - 1]; stackptr := stackptr - 1; if c = '+' then a := a + b; elif c = '-' then a := a - b; elif c = '*' then a := a * b; elif c = '/' then if b = 0 then ok := false; break; fi; a := a / b; else ok := false; break; fi; stack[stackptr] := a; fi; od; if ok and stackptr = 1 and Size(cur) = 0 then if stack[1] = 24 then Print("Good !\n"); break; else Print("Bad value: ", stack[1], "\n"); continue; fi; fi; Print("Invalid expression\n"); fi; od; od; CloseStream(input); end;
- example session
- type "end" to quit the game, "next" to try another list of digits
gap> Play24(); [ 7, 6, 8, 5 ] 86*75-/ Good ! [ 5, 9, 2, 7 ] end gap></lang>
Go
RPN solution. <lang go>package main
import (
"fmt" "math" "math/rand" "time"
)
func main() {
rand.Seed(time.Now().Unix()) n := make([]rune, 4) for i := range n { n[i] = rune(rand.Intn(9) + '1') } fmt.Printf("Your numbers: %c\n", n) fmt.Print("Enter RPN: ") var expr string fmt.Scan(&expr) if len(expr) != 7 { fmt.Println("invalid. expression length must be 7." + " (4 numbers, 3 operators, no spaces)") return } stack := make([]float64, 0, 4) for _, r := range expr { if r >= '0' && r <= '9' { if len(n) == 0 { fmt.Println("too many numbers.") return } i := 0 for n[i] != r { i++ if i == len(n) { fmt.Println("wrong numbers.") return } } n = append(n[:i], n[i+1:]...) stack = append(stack, float64(r-'0')) continue } if len(stack) < 2 { fmt.Println("invalid expression syntax.") return } switch r { case '+': stack[len(stack)-2] += stack[len(stack)-1] case '-': stack[len(stack)-2] -= stack[len(stack)-1] case '*': stack[len(stack)-2] *= stack[len(stack)-1] case '/': stack[len(stack)-2] /= stack[len(stack)-1] default: fmt.Printf("%c invalid.\n", r) return } stack = stack[:len(stack)-1] } if math.Abs(stack[0]-24) > 1e-6 { fmt.Println("incorrect.", stack[0], "!= 24") } else { fmt.Println("correct.") }
}</lang> Example game:
Your numbers: [5 8 1 3] Enter RPN: 83-5*1- correct.
Gosu
<lang Gosu> uses java.lang.Double uses java.lang.Integer uses java.util.ArrayList uses java.util.List uses java.util.Scanner uses java.util.Stack
function doEval( scanner : Scanner, allowed : List<Integer> ) : double {
var stk = new Stack<Double>()
while( scanner.hasNext() ) { if( scanner.hasNextInt() ) { var n = scanner.nextInt()
// Make sure they're allowed to use n if( n <= 0 || n >= 10 ) { print( n + " isn't allowed" ) return 0 } var idx = allowed.indexOf( n ) if( idx == -1 ) { print( "You aren't allowed to use so many " + n + "s!" ) return 0 }
// Add the input number to the stack stk.push( new Double( n ) )
// Mark n as used allowed.remove( idx ) } else { // It has to be an operator... if( stk.size() < 2 ) { print( "Invalid Expression: Stack underflow!" ) return 0 }
// Gets the next operator as a single character token var s = scanner.next("[\\+-/\\*]")
// Get the operands var r = stk.pop().doubleValue() var l = stk.pop().doubleValue()
// Determine which operator and invoke it if( s.equals( "+" ) ) { stk.push( new Double( l + r ) ) } else if( s.equals( "-" ) ) { stk.push( new Double( l - r ) ) } else if( s.equals( "*" ) ) { stk.push( new Double( l * r ) ) } else if( s.equals( "/" ) ) { if( r == 0.0 ) { print( "Invalid Expression: Division by zero!" ) return 0 } stk.push( new Double( l / r ) ) } else { print( "Internal Error: looking for operator yielded '" + s + "'" ) return 0 } } }
// Did they skip any numbers? if( allowed.size() != 0 ) { print( "You didn't use ${allowed}" ) return 0 }
// Did they use enough operators? if( stk.size() != 1 ) { print( "Invalid Expression: Not enough operators!" ) return 0 }
return stk.pop().doubleValue()
}
// Pick 4 random numbers from [1..9] var nums = new ArrayList<Integer>() var gen = new java.util.Random( new java.util.Date().getTime() ) for( i in 0..3 ) {
nums.add( gen.nextInt(9) + 1 )
}
// Prompt the user print( "Using addition, subtraction, multiplication and division, write an" ) print( "expression that evaluates to 24 using" ) print( "${nums.get(0)}, ${nums.get(1)}, ${nums.get(2)} and ${nums.get(3)}" ) print( "" ) print( "Please enter your expression in RPN" )
// Build a tokenizer over a line of input var sc = new Scanner( new java.io.BufferedReader( new java.io.InputStreamReader( java.lang.System.in ) ).readLine() )
// eval the expression var val = doEval( sc, nums )
// winner? if( java.lang.Math.abs( val - 24.0 ) < 0.001 ) {
print( "You win!" )
} else {
print( "You lose!" )
} </lang>
Groovy
This solution breaks strict adherence to the rules in only one way: any line that starts with the letter "q" causes the game to quit. <lang groovy>final random = new Random() final input = new Scanner(System.in)
def evaluate = { expr ->
if (expr == 'QUIT') { return 'QUIT' } else { try { Eval.me(expr.replaceAll(/(\d)/, '$1.0')) } catch (e) { 'syntax error' } }
}
def readGuess = { digits ->
while (true) { print "Enter your guess using ${digits} (q to quit): " def expr = input.nextLine() switch (expr) { case ~/^[qQ].*/: return 'QUIT'
case ~/.*[^\d\s\+\*\/\(\)-].*/: def badChars = expr.replaceAll(~/[\d\s\+\*\/\(\)-]/, ) println "invalid characters in input: ${(badChars as List) as Set}" break
case { (it.replaceAll(~/\D/, ) as List).sort() != ([]+digits).sort() }: println you didn't use the right digits break
case ~/.*\d\d.*/: println 'no multi-digit numbers allowed' break
default: return expr } }
}
def digits = (1..4).collect { (random.nextInt(9) + 1) as String }
while (true) {
def guess = readGuess(digits) def result = evaluate(guess) switch (result) { case 'QUIT': println 'Awwww. Maybe next time?' return case 24: println 'Yes! You got it.' return case 'syntax error': println "A ${result} was found in ${guess}" break default: println "Nope: ${guess} == ${result}, not 24" println 'One more try, then?' }
}</lang>
Sample Run:
$ groovy TwentyFour.gsh Enter your guess using [4, 8, 3, 6] (q to quit): 4836 no multi-digit numbers allowed Enter your guess using [4, 8, 3, 6] (q to quit): 4 ++ ++ 8/ 3-6 A syntax error was found in 4 ++ ++ 8/ 3-6 Enter your guess using [4, 8, 3, 6] (q to quit): btsjsb invalid characters in input: [t, s, b, j] Enter your guess using [4, 8, 3, 6] (q to quit): 1+3+2+2 you didn't use the right digits Enter your guess using [4, 8, 3, 6] (q to quit): q Awwww. Maybe next time? $ groovy TwentyFour.gsh Enter your guess using [6, 3, 2, 6] (q to quit): 6+6+3+2 Nope: 6+6+3+2 == 17.0, not 24 One more try, then? Enter your guess using [6, 3, 2, 6] (q to quit): (6*3 - 6) * 2 Yes! You got it.
Haskell
<lang Haskell>import Data.List (sort) import Data.Char (isDigit) import Data.Maybe (fromJust) import Control.Monad (foldM) import System.Random (randomRs, getStdGen) import System.IO (hSetBuffering, stdout, BufferMode(NoBuffering))
main = do
hSetBuffering stdout NoBuffering mapM_ putStrLn [ "THE 24 GAME\n" , "Given four digits in the range 1 to 9" , "Use the +, -, *, and / operators in reverse polish notation" , "To show how to make an answer of 24.\n" ] digits <- fmap (sort . take 4 . randomRs (1, 9)) getStdGen :: IO [Int] putStrLn ("Your digits: " ++ unwords (fmap show digits)) guessLoop digits where guessLoop digits = putStr "Your expression: " >> fmap (processGuess digits . words) getLine >>= either (\m -> putStrLn m >> guessLoop digits) putStrLn
processGuess _ [] = Right "" processGuess digits xs
| not matches = Left "Wrong digits used" where matches = digits == (sort . fmap read $ filter (all isDigit) xs)
processGuess digits xs = calc xs >>= check
where check 24 = Right "Correct" check x = Left (show (fromRational (x :: Rational)) ++ " is wrong")
-- A Reverse Polish Notation calculator with full error handling calc xs =
foldM simplify [] xs >>= \ns -> (case ns of [n] -> Right n _ -> Left "Too few operators")
simplify (a:b:ns) s
| isOp s = Right ((fromJust $ lookup s ops) b a : ns)
simplify _ s
| isOp s = Left ("Too few values before " ++ s)
simplify ns s
| all isDigit s = Right (fromIntegral (read s) : ns)
simplify _ s = Left ("Unrecognized symbol: " ++ s)
isOp v = elem v $ fmap fst ops
ops = [("+", (+)), ("-", (-)), ("*", (*)), ("/", (/))]</lang>
HicEst
<lang HicEst>DIMENSION digits(4), input_digits(100), difference(4) CHARACTER expression*100, prompt*100, answers='Wrong,Correct,', protocol='24 game.txt'
1 digits = CEILING( RAN(9) ) 2 DLG(Edit=expression, Text=digits, TItle=prompt)
READ(Text=expression, ItemS=n) input_digits IF(n == 4) THEN ALIAS(input_digits,1, input,4) SORT(Vector=digits, Sorted=digits) SORT(Vector=input, Sorted=input) difference = ABS(digits - input) IF( SUM(difference) == 0 ) THEN EDIT(Text=expression, ScaNnot='123456789+-*/ ()', GetPos=i, CoPyto=prompt) IF( i > 0 ) THEN prompt = TRIM(expression) // ': ' //TRIM(prompt) // ' is an illegal character' ELSE prompt = TRIM(expression) // ': Syntax error' result = XEQ(expression, *2) ! on error branch to label 2 EDIT(Text=answers, ITeM=(result==24)+1, Parse=answer) WRITE(Text=prompt, Name) TRIM(expression)//': ', answer, result ENDIF ELSE WRITE(Text=prompt) TRIM(expression), ': You used ', input, ' instead ', digits ENDIF ELSE prompt = TRIM(expression) // ': Instead 4 digits you used ' // n ENDIF
OPEN(FIle=protocol, APPend) WRITE(FIle=protocol, CLoSe=1) prompt
DLG(TItle=prompt, Button='>2:Try again', B='>1:New game', B='Quit')
END</lang> <lang HicEst>4 + 8 + 7 + 5: You used 4 5 7 8 instead 4 4 7 8 4 + 8 + 7 + a: Instead 4 digits you used 3 4 + 8 + 7 + a + 4: a is an illegal character 4 + 8 + 7a + 4: a is an illegal character 4 + 8 + 7 + 4:; answer=Wrong; result=23; 4 * 7 - 8 + 4:; answer=Correct; result=24;</lang>
Huginn
<lang huginn>#! /bin/sh exec huginn --no-argv -E "${0}"
- ! huginn
import Algorithms as algo; import Mathematics as math; import RegularExpressions as re;
make_game( rndGen_ ) {
board = ""; for ( i : algo.range( 4 ) ) { board += ( " " + string( character( rndGen_.next() + integer( '1' ) ) ) ); } return ( board.strip() );
}
main() {
rndGen = math.randomizer( 9 ); no = 0; dd = re.compile( "\\d\\d" ); while ( true ) { no += 1; board = make_game( rndGen ); print( "Your four digits: {}\nExpression {}: ".format( board, no ) ); line = input(); if ( line == none ) { print( "\n" ); break; } line = line.strip(); try { if ( line == "q" ) { break; } if ( ( pos = line.find_other_than( "{}+-*/() ".format( board ) ) ) >= 0 ) { print( "Invalid input found at: {}, `{}`\n".format( pos, line ) ); continue; } if ( dd.match( line ).matched() ) { print( "Digit concatenation is forbidden.\n" ); continue; } res = real( line ); if ( res == 24.0 ) { print( "Thats right!\n" ); } else { print( "Bad answer!\n" ); } } catch ( Exception e ) { print( "Not an expression: {}\n".format( e.what() ) ); } } return ( 0 );
}</lang>
Icon and Unicon
This plays the game of 24 using a simplified version of the code from the Arithmetic evaluation task. <lang Icon>invocable all link strings # for csort, deletec
procedure main() help() repeat {
every (n := "") ||:= (1 to 4, string(1+?8)) writes("Your four digits are : ") every writes(!n," ") write() e := trim(read()) | fail case e of { "q"|"quit": return "?"|"help": help() default: { e := deletec(e,' \t') # no whitespace d := deletec(e,~&digits) # just digits if csort(n) ~== csort(d) then # and only the 4 given digits write("Invalid repsonse.") & next
if e ? (ans := eval(E()), pos(0)) then # parse and evaluate if ans = 24 then write("Congratulations you win!") else write("Your answer was ",ans,". Try again.") else write("Invalid expression.") } } }
end
procedure eval(X) #: return the evaluated AST
if type(X) == "list" then { x := eval(get(X)) while x := get(X)(real(x), real(eval(get(X) | stop("Malformed expression.")))) } return \x | X
end
procedure E() #: expression
put(lex := [],T()) while put(lex,tab(any('+-*/'))) do put(lex,T()) suspend if *lex = 1 then lex[1] else lex # strip useless []
end
procedure T() #: Term
suspend 2(="(", E(), =")") | # parenthesized subexpression, or ... tab(any(&digits)) # just a value
end
procedure help() return write(
"Welcome to 24\n\n", "Combine the 4 given digits to make 24 using only + - * / and ( ).\n ", "All operations have equal precedence and are evaluated left to right.\n", "Combining (concatenating) digits is not allowed.\n", "Enter 'help', 'quit', or an expression.\n")
end</lang>
strings.icn provides deletec and sortc
- Output:
Welcome to 24 The object of the game is to combine the 4 given digits using only + - * / and ( ). All operations have equal precedence and are evaluated left to right. Combining (concatenating) digits is not allowed. Enter 'help', 'quit', or an expression. Your four digits are : 8 1 7 2 8*2+(7+1) Congratulations you win! Your four digits are : 4 2 7 6 7*6+(4*2) Your answer was 50. Try again. Your four digits are : 7 7 8 8 77-88 Invalid expression. Your four digits are : 9 3 2 3 9+3+2+3+ Malformed expression.
J
<lang J>require'misc' deal=: 1 + ? bind 9 9 9 9 rules=: smoutput bind 'see http://en.wikipedia.org/wiki/24_Game' input=: prompt @ ('enter 24 expression using ', ":, ': '"_)
wellformed=: (' '<;._1@, ":@[) -:&(/:~) '(+-*%)' -.&;:~ ] is24=: 24 -: ". ::0:@]
respond=: (;:'no yes') {::~ wellformed * is24
game24=: (respond input)@deal@rules</lang>
Example use:
game24 '' see http://en.wikipedia.org/wiki/24_Game enter 24 expression using 6 5 9 4: 6+5+9+4 yes game24 '' see http://en.wikipedia.org/wiki/24_Game enter 24 expression using 3 3 3 3: 3+3+3+3+3+3+3+3 no
Java
<lang java>import java.util.*;
public class Game24 {
static Random r = new Random();
public static void main(String[] args) {
int[] digits = randomDigits(); Scanner in = new Scanner(System.in);
System.out.print("Make 24 using these digits: "); System.out.println(Arrays.toString(digits)); System.out.print("> ");
Stack<Float> s = new Stack<>(); long total = 0; for (char c : in.nextLine().toCharArray()) { if ('0' <= c && c <= '9') { int d = c - '0'; total += (1 << (d * 5)); s.push((float) d); } else if ("+/-*".indexOf(c) != -1) { s.push(applyOperator(s.pop(), s.pop(), c)); } } if (tallyDigits(digits) != total) System.out.print("Not the same digits. "); else if (Math.abs(24 - s.peek()) < 0.001F) System.out.println("Correct!"); else System.out.print("Not correct."); }
static float applyOperator(float a, float b, char c) { switch (c) { case '+': return a + b; case '-': return b - a; case '*': return a * b; case '/': return b / a; default: return Float.NaN; } }
static long tallyDigits(int[] a) { long total = 0; for (int i = 0; i < 4; i++) total += (1 << (a[i] * 5)); return total; }
static int[] randomDigits() { int[] result = new int[4]; for (int i = 0; i < 4; i++) result[i] = r.nextInt(9) + 1; return result; }
}</lang>
- Output:
Make 24 using these digits: [1, 2, 4, 8] > 12*48+* Correct!
JavaScript
<lang javascript> function twentyfour(numbers, input) {
var invalidChars = /[^\d\+\*\/\s-\(\)]/;
var validNums = function(str) { // Create a duplicate of our input numbers, so that // both lists will be sorted. var mnums = numbers.slice(); mnums.sort();
// Sort after mapping to numbers, to make comparisons valid. return str.replace(/[^\d\s]/g, " ") .trim() .split(/\s+/) .map(function(n) { return parseInt(n, 10); }) .sort() .every(function(v, i) { return v === mnums[i]; }); };
var validEval = function(input) { try { return eval(input); } catch (e) { return {error: e.toString()}; } };
if (input.trim() === "") return "You must enter a value."; if (input.match(invalidChars)) return "Invalid chars used, try again. Use only:\n + - * / ( )"; if (!validNums(input)) return "Wrong numbers used, try again."; var calc = validEval(input); if (typeof calc !== 'number') return "That is not a valid input; please try again."; if (calc !== 24) return "Wrong answer: " + String(calc) + "; please try again."; return input + " == 24. Congratulations!";
};
// I/O below.
while (true) {
var numbers = [1, 2, 3, 4].map(function() { return Math.floor(Math.random() * 8 + 1); });
var input = prompt( "Your numbers are:\n" + numbers.join(" ") + "\nEnter expression. (use only + - * / and parens).\n", +"'x' to exit.", "");
if (input === 'x') { break; } alert(twentyfour(numbers, input));
} </lang>
Julia
This implementation, because it is based on the Julia parser and evaluator, allows the user to enter arbitrary infix expressions, including parentheses. (These expressions are checked to ensure that they only include the allowed operations on integer literals.) <lang julia>validexpr(ex::Expr) = ex.head == :call && ex.args[1] in [:*,:/,:+,:-] && all(validexpr, ex.args[2:end]) validexpr(ex::Int) = true validexpr(ex::Any) = false findnumbers(ex::Number) = Int[ex] findnumbers(ex::Expr) = vcat(map(findnumbers, ex.args)...) findnumbers(ex::Any) = Int[] function twentyfour()
digits = sort!(rand(1:9, 4)) while true print("enter expression using $digits => ") ex = parse(readline()) try validexpr(ex) || error("only *, /, +, - of integers is allowed") nums = sort!(findnumbers(ex)) nums == digits || error("expression $ex used numbers $nums != $digits") val = eval(ex) val == 24 || error("expression $ex evaluated to $val, not 24") println("you won!") return catch e if isa(e, ErrorException) println("incorrect: ", e.msg) else rethrow() end end end
end</lang>
- Output:
julia> twentyfour() enter expression using [2,5,8,9] => 5 * 2 - 8 + 9 incorrect: expression (5 * 2 - 8) + 9 evaluated to 11, not 24 enter expression using [2,5,8,9] => 5 * 5 + 2 + 8 - 9 incorrect: expression (5 * 5 + 2 + 8) - 9 used numbers [2,5,5,8,9] != [2,5,8,9] enter expression using [2,5,8,9] => 8*2*2 incorrect: expression 8 * 2 * 2 used numbers [2,2,8] != [2,5,8,9] enter expression using [2,5,8,9] => (8 + 9) + (5 + 2) you won!
Kotlin
<lang scala>import java.util.Random import java.util.Scanner import java.util.Stack
internal object Game24 {
fun run() { val r = Random() val digits = IntArray(4).map { r.nextInt(9) + 1 } println("Make 24 using these digits: $digits") print("> ")
val s = Stack<Float>() var total = 0L val cin = Scanner(System.`in`) for (c in cin.nextLine()) { when (c) { in '0'..'9' -> { val d = c - '0' total += (1 shl (d * 5)).toLong() s += d.toFloat() } else -> if ("+/-*".indexOf(c) != -1) { s += c.applyOperator(s.pop(), s.pop()) } } }
when { tally(digits) != total -> print("Not the same digits. ") s.peek().compareTo(target) == 0 -> println("Correct!") else -> print("Not correct.") } }
private fun Char.applyOperator(a: Float, b: Float) = when (this) { '+' -> a + b '-' -> b - a '*' -> a * b '/' -> b / a else -> Float.NaN }
private fun tally(a: List<Int>): Long = a.reduce({ t, i -> t + (1 shl (i * 5)) }).toLong()
private val target = 24
}
fun main(args: Array<String>) = Game24.run()</lang>
Lasso
This solution requires web input from the user via a form of the expression.
On submit the expression is checked for valid chars, that the integers are valid and in the original array (which also takes care of non-duplicate integers), and that the integers are not in consecutive positions.
If a valid expression it is evaluated, and the result and success state shown to the user. <lang Lasso>[ if(sys_listunboundmethods !>> 'randoms') => { define randoms()::array => { local(out = array) loop(4) => { #out->insert(math_random(9,1)) } return #out } } if(sys_listunboundmethods !>> 'checkvalid') => { define checkvalid(str::string, nums::array)::boolean => { local(chk = array('*','/','+','-','(',')',' '), chknums = array, lastintpos = -1, poscounter = 0) loop(9) => { #chk->insert(loop_count) } with s in #str->values do => { #poscounter++ #chk !>> #s && #chk !>> integer(#s) ? return false integer(#s) > 0 && #lastintpos + 1 >= #poscounter ? return false integer(#s) > 0 ? #chknums->insert(integer(#s)) integer(#s) > 0 ? #lastintpos = #poscounter } #chknums->size != 4 ? return false #nums->sort #chknums->sort loop(4) => { #nums->get(loop_count) != #chknums(loop_count) ? return false } return true } } if(sys_listunboundmethods !>> 'executeexpr') => { define executeexpr(expr::string)::integer => { local(keep = string) with i in #expr->values do => { if(array('*','/','+','-','(',')') >> #i) => { #keep->append(#i) else integer(#i) > 0 ? #keep->append(decimal(#i)) } } return integer(sourcefile('['+#keep+']','24game',true,true)->invoke) } }
local(numbers = array, exprsafe = true, exprcorrect = false, exprresult = 0) if(web_request->param('nums')->asString->size) => { with n in web_request->param('nums')->asString->split(',') do => { #numbers->insert(integer(#n->trim&)) } }
- numbers->size != 4 ? #numbers = randoms()
if(web_request->param('nums')->asString->size) => { #exprsafe = checkvalid(web_request->param('expr')->asString,#numbers) if(#exprsafe) => { #exprresult = executeexpr(web_request->param('expr')->asString) #exprresult == 24 ? #exprcorrect = true } }
]
24 Game
Rules:
Enter an expression that evaluates to 24
- Only multiplication, division, addition, and subtraction operators/functions are allowed.
- Brackets are allowed.
- Forming multiple digit numbers from the supplied digits is disallowed. (So an answer of 12+12 when given 1, 2, 2, and 1 is wrong).
- The order of the digits when given does not have to be preserved.
Numbers
[#numbers->join(', ')] (<a href="?">Reload</a>)
[!#exprsafe ? '
Please provide a valid expression
']
<form><input type="hidden" value="[#numbers->join(',')]" name="nums"><input type="text" name="expr" value="[web_request->param('expr')->asString]"><input type="submit" name="submit" value="submit"></form> [if(#exprsafe)]
Result: [#exprresult] [#exprcorrect ? 'is CORRECT!' | 'is incorrect']
[/if]</lang>
Liberty BASIC
<lang lb>dim d(4) dim chk(4) print "The 24 Game" print print "Given four digits and using just the +, -, *, and / operators; and the" print "possible use of brackets, (), enter an expression that equates to 24."
do
d$="" for i = 1 to 4 d(i)=int(rnd(1)*9)+1 '1..9 chk(i)=d(i) d$=d$;d(i) 'valid digits, to check with Instr next
print print "These are your four digits: "; for i = 1 to 4 print d(i);left$(",",i<>4); next print
Print "Enter expression:" Input "24 = ";expr$ 'check expr$ for validity
'check right digits used failed = 0 for i = 1 to len(expr$) c$=mid$(expr$,i,1) if instr("123456789", c$)<>0 then 'digit if instr(d$, c$)=0 then failed = 1: exit for if i>1 and instr("123456789", mid$(expr$,i-1,1))<>0 then failed = 2: exit for for j =1 to 4 if chk(j)=val(c$) then chk(j)=0: exit for next end if next if failed=1 then print "Wrong digit (";c$;")" goto [fail] end if
if failed=2 then print "Multiple digit numbers is disallowed." goto [fail] end if
'check all digits used if chk(1)+ chk(2)+ chk(3)+ chk(4)<>0 then print "Not all digits used" goto [fail] end if
'check valid operations failed = 0 for i = 1 to len(expr$) c$=mid$(expr$,i,1) if instr("+-*/()"+d$, c$)=0 then failed = 1: exit for next if failed then print "Wrong operation (";c$;")" goto [fail] end if 'some errors (like brackets) trapped by error handler Err$="" res=evalWithErrCheck(expr$) if Err$<>"" then print "Error in expression" goto [fail] end if if res = 24 then print "Correct!" else print "Wrong! (you got ";res ;")" end if
[fail]
Input "Play again (y/n)? "; ans$
loop while ans$="y" end
function evalWithErrCheck(expr$)
on error goto [handler] evalWithErrCheck=eval(expr$) exit function
[handler] end function</lang>
LiveCode
GUI version
1. Open livecode and create a new mainstack
2. Create 3 fields and 1 button
3. label fields "YourNumbersField", "EvalField" and "AnswerField"
4. label button "StartButton"
5. Add the following to the code of "StartButton"<lang livecode>on mouseUp
put empty into fld "EvalField" put empty into fld "AnswerField" put random(9) & comma & random(9) & comma & random(9) & comma & random(9) into fld "YourNumbersField"
end mouseUp</lang> 6. Add the following to the code of field "EvalField"<lang livecode> on keyDown k
local ops, nums, allowedKeys, numsCopy, expr put "+,-,/,*,(,)" into ops put the text of fld "YourNumbersField" into nums put the text of fld "EvalField" into expr if matchText(expr & k,"\d\d") then answer "You can't enter 2 digits together" exit keyDown end if repeat with n = 1 to the number of chars of expr if offset(char n of expr, nums) > 0 then delete char offset(char n of expr, nums) of nums end if end repeat put ops & comma & nums into allowedKeys if k is among the items of allowedKeys then put k after expr delete char offset(k, nums) of nums replace comma with empty in nums try put the value of merge("expr") into fld "AnswerField" if the value of fld "AnswerField" is 24 and nums is empty then answer "You win!" end if end try pass keyDown else exit keyDown end if
end keyDown</lang>
Locomotive Basic
<lang locobasic>10 CLS:RANDOMIZE TIME 20 PRINT "The 24 Game" 30 PRINT "===========":PRINT 40 PRINT "Enter an arithmetic expression" 50 PRINT "that evaluates to 24," 60 PRINT "using only the provided digits" 70 PRINT "and +, -, *, /, (, )." 80 PRINT "(Just hit Return for new digits.)" 90 ' create new digits 100 FOR i=1 TO 4:a(i)=INT(RND*9)+1:NEXT 110 PRINT 120 PRINT "The digits are";a(1);a(2);a(3);a(4) 130 PRINT 140 ' user enters solution 150 INPUT "Your solution";s$ 160 IF s$="" THEN PRINT "Creating new digits...":GOTO 100 170 GOTO 300 180 ' a little hack to create something like an EVAL function 190 OPENOUT "exp.bas" 200 PRINT #9,"1000 x="s$":return" 210 CLOSEOUT 220 CHAIN MERGE "exp",240 230 ' now evaluate the expression 240 ON ERROR GOTO 530 250 GOSUB 1000 260 IF x=24 THEN PRINT "Well done!":END 270 PRINT "No, this evaluates to"x:PRINT "Please try again." 280 GOTO 150 290 ' check input for correctness 300 FOR i=1 TO LEN(s$) 310 q=ASC(MID$(s$,i,1)) 320 IF q=32 OR (q>39 AND q<44) OR q=45 OR (q>46 AND q<58) THEN NEXT 330 IF i-1=LEN(s$) THEN 370 340 PRINT "Bad character in expression:"CHR$(q) 350 PRINT "Try again":GOTO 150 360 ' new numbers in solution? 370 FOR i=1 TO LEN(s$)-1 380 q=ASC(MID$(s$,i,1)):p=ASC(MID$(s$,i+1,1)) 390 IF q>47 AND q<58 AND p>47 AND p<58 THEN PRINT "No forming of new numbers, please!":GOTO 150 400 NEXT 410 FOR i=1 TO 9:orig(i)=0:guess(i)=0:NEXT 420 FOR i=1 TO 4:orig(a(i))=orig(a(i))+1:NEXT 430 FOR i=1 TO LEN(s$) 440 v$=MID$(s$,i,1) 450 va=ASC(v$)-48 460 IF va>0 AND va<10 THEN guess(va)=guess(va)+1 470 NEXT 480 FOR i=1 TO 9 490 IF guess(i)<>orig(i) THEN PRINT "Only use all the provided digits!":GOTO 150 500 NEXT 510 GOTO 190 520 ' syntax error, e.g. non-matching parentheses 530 PRINT "Error in expression, please try again." 540 RESUME 150</lang>
Note: The program needs a writable disk in the active disk drive.
Logo
<lang logo>; useful constants make "false 1=0 make "true 1=1 make "lf char 10 make "sp char 32
- non-digits legal in expression
make "operators (lput sp [+ - * / \( \)])
- display help message
to show_help :digits
type lf print sentence quoted [Using only these digits:] :digits print sentence quoted [and these operators:] [* / + -] print quoted [\(and parentheses as needed\),] print quoted [enter an arithmetic expression which evaluates to exactly 24.] type lf print quoted [Enter \"!\" to get fresh numbers.] print quoted [Enter \"q\" to quit.] type lf
end
make "digits [] make "done false until [done] [
if empty? digits [ make "digits (map [(random 9) + 1] [1 2 3 4]) ]
(type "Solution sp "for sp digits "? sp ) make "expression readrawline
ifelse [expression = "?] [
show_help digits
] [ifelse [expression = "q] [
print "Bye! make "done true
] [ifelse [expression = "!] [
make "digits []
] [ make "exprchars ` expression make "allowed (sentence digits operators)
ifelse (member? false (map [[c] member? c allowed] exprchars)) [ (print quoted [Illegal character in input.]) ] [ catch "error [ make "syntax_error true make "testval (run expression) make "syntax_error false ] ifelse syntax_error [ (print quoted [Invalid expression.]) ] [ ifelse (testval = 24) [ print quoted [You win!] make "done true ] [ (print (sentence quoted [Incorrect \(got ] testval quoted [instead of 24\).])) ] ] ] ]]]
] bye</lang>
- Output:
Solution for 3 8 9 5? ? Using only these digits: 3 8 9 5 and these operators: * / + - (and parentheses as needed), enter an arithmetic expression which evaluates to exactly 24. Enter "!" to get fresh numbers. Enter "q" to quit. Solution for 3 8 9 5? ! Solution for 9 2 8 5? 9+2+8+5 You win!
Lua
<lang lua> local function help() print [[
The 24 Game
Given any four digits in the range 1 to 9, which may have repetitions, Using just the +, -, *, and / operators; and the possible use of brackets, (), show how to make an answer of 24.
An answer of "q" will quit the game. An answer of "!" will generate a new set of four digits.
Note: you cannot form multiple digit numbers from the supplied digits, so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed.
]]
end
local function generate(n) result = {} for i=1,n do result[i] = math.random(1,9) end return result end
local function check(answer, digits) local adig = {} local ddig = {} local index local lastWasDigit = false for i=1,9 do adig[i] = 0 ddig[i] = 0 end allowed = {['(']=true,[')']=true,[' ']=true,['+']=true,['-']=true,['*']=true,['/']=true,['\t']=true,['1']=true,['2']=true,['3']=true,['4']=true,['5']=true,['6']=true,['7']=true,['8']=true,['9']=true} for i=1,string.len(answer) do if not allowed[string.sub(answer,i,i)] then return false end index = string.byte(answer,i)-48 if index > 0 and index < 10 then if lastWasDigit then return false end lastWasDigit = true adig[index] = adig[index] + 1 else lastWasDigit = false end end for i,digit in next,digits do ddig[digit] = ddig[digit]+1 end for i=1,9 do if adig[i] ~= ddig[i] then return false end end return loadstring('return '..answer)() end
local function game24() help() math.randomseed(os.time()) math.random() local digits = generate(4) local trial = 0 local answer = 0 local ans = false io.write 'Your four digits:' for i,digit in next,digits do io.write (' ' .. digit) end print() while ans ~= 24 do trial = trial + 1 io.write("Expression "..trial..": ") answer = io.read() if string.lower(answer) == 'q' then break end if answer == '!' then digits = generate(4) io.write ("New digits:") for i,digit in next,digits do io.write (' ' .. digit) end print() else ans = check(answer,digits) if ans == false then print ('The input '.. answer ..' was wonky!') else print (' = '.. ans) if ans == 24 then print ("Thats right!") end end end end end game24()</lang>
Alternately, using the lpeg.re
module:
<lang lua>function twentyfour()
print [[ The 24 Game Given any four digits in the range 1 to 9, which may have repetitions, Using just the +, -, *, and / operators; and the possible use of brackets, (), show how to make an answer of 24. An answer of "q" will quit the game. An answer of "!" will generate a new set of four digits. Note: you cannot form multiple digit numbers from the supplied digits, so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed. ]] expr = re.compile[[ --matches properly formatted infix expressions and returns all numerals as captures expr <- (!.) / (<paren> / <number>) (<ws> <oper> <ws> <expr>)? number <- {[0-9]} ws <- " "* oper <- [-+/*] paren <- "(" <ws> <expr> <ws> ")" ]] local val_t = {math.random(9), math.random(9), math.random(9), math.random(9)} table.sort(val_t) print("the digits are " .. table.concat(val_t, ", ")) local ex = io.read() a, b, c, d, e = expr:match(ex) if a and b and c and d and not e then --if there is a fifth numeral the player is cheating local digs = {a + 0, b + 0, c + 0, d + 0} local flag = false -- (terrorism!) table.sort(digs) for i = 1, 4 do
flag = digs[i] ~= val_t[i] and not print"Wrong digits!" or flag
end if not flag and loadstring("return " .. ex)() == 24 then print"You win!" else print"You lose." end else print"wat" --expression could not be interpreted as arithmetic end
end twentyfour()</lang>
Maple
Click here to try this game online. <lang maple>play24 := module() export ModuleApply; local cheating; cheating := proc(input, digits) local i, j, stringDigits; use StringTools in stringDigits := Implode([seq(convert(i, string), i in digits)]); for i in digits do for j in digits do if Search(cat(convert(i, string), j), input) > 0 then return true, ": Please don't combine digits to form another number." end if; end do; end do; for i in digits do if CountCharacterOccurrences(input, convert(i, string)) < CountCharacterOccurrences(stringDigits, convert(i, string)) then return true, ": Please use all digits."; end if; end do; for i in digits do if CountCharacterOccurrences(input, convert(i, string)) > CountCharacterOccurrences(stringDigits, convert(i, string)) then return true, ": Please only use a digit once."; end if; end do; for i in input do try if type(parse(i), numeric) and not member(parse(i), digits) then return true, ": Please only use the digits you were given."; end if; catch: end try; end do; return false, ""; end use; end proc:
ModuleApply := proc() local replay, digits, err, message, answer; randomize(): replay := "": while not replay = "END" do if not replay = "YES" then digits := [seq(rand(1..9)(), i = 1..4)]: end if; err := true: while err do message := ""; printf("Please make 24 from the digits: %a. Press enter for a new set of numbers or type END to quit\n", digits); answer := StringTools[UpperCase](readline()); if not answer = "" and not answer = "END" then try if not type(parse(answer), numeric) then error; elif cheating(answer, digits)[1] then message := cheating(answer, digits)[2]; error; end if; err := false; catch: printf("Invalid Input%s\n\n", message); end try; else err := false; end if; end do: if not answer = "" and not answer = "END" then if parse(answer) = 24 then printf("You win! Do you wish to play another game? (Press enter for a new set of numbers or END to quit.)\n"); replay := StringTools[UpperCase](readline()); else printf("Your expression evaluated to %a. Try again!\n", parse(answer)); replay := "YES"; end if; else replay := answer; end if;
printf("\n"); end do: printf("GAME OVER\n"); end proc: end module:
play24();</lang>
- Output:
Please make 24 from the digits: [4, 7, 6, 8]. Press enter for a new set of numbers or type END to quit You win! Do you wish to play another game? (Press enter for a new set of numbers or END to quit.) Please make 24 from the digits: [3, 7, 4, 7]. Press enter for a new set of numbers or type END to quit Your expression evaluated to 21. Try again! Please make 24 from the digits: [3, 7, 4, 7]. Press enter for a new set of numbers or type END to quit GAME OVER
Mathematica
Since Mathematica hasn't historically had good custom I/O support (the command-line allowed all operations, not very good for UI-generation), I had to roll some custom GUI (with a text box), which requires Mathematica 6.
Most of the job is already done by Mathematica (the expression conversion); in fact, it is too good—it automatically converts ex. 3/4 to Times[3, Power[4, -1]], which we have to specifically test for so that real powers don't get through.
<lang Mathematica>isLegal[n_List, x_String] :=
Quiet[Check[ With[{h = ToExpression[x, StandardForm, HoldForm]}, If[Cases[Level[h, {2, \[Infinity]}, Hold, Heads -> True], Except[_Integer | Plus | _Plus | Times | _Times | Power | Power[_, -1]]] === {} && Sort[Level[h /. Power[q_, -1] -> q, {-1}] /. q_Integer -> Abs[q]] === Sort[n], ReleaseHold[h]]], Null]]
Grid[{{Button[
"new numbers", {a, b, c, d} = Table[RandomInteger[{1, 9}], {4}]], InputField[Dynamic[x], String]}, {Dynamic[{a, b, c, d}], Dynamic[Switch[isLegal[{a, b, c, d}, x], Null, "Sorry, that is invalid.", 24, "Congrats! That's 24!", _, "Sorry, that makes " <> ToString[ToExpression@x, InputForm] <> ", not 24."]]}}]</lang>
MATLAB / Octave
<lang Matlab> function twentyfour()
N = 4; n = ceil(rand(1,N)*9); printf('Generate a equation with the numbers %i, %i, %i, %i and +, -, *, /, () operators ! \n',n); s = input(': ','s'); t = s; for k = 1:N, [x,t] = strtok(t,'+-*/() \t'); if length(x)~=1, error('invalid sign %s\n',x); end; y = x-'0'; if ~(0 < y & y < 10) error('invalid sign %s\n',x); end; z(1,k) = y; end; if any(sort(z)-sort(n)) error('numbers do not match.\n'); end;
val = eval(s); if val==24, fprintf('expression "%s" results in %i.\n',s,val); else fprintf('expression "%s" does not result in 24 but %i.\n',s,val); end; </lang>
MiniScript
We use a simple recursive descent parser, with a bit of extra code to make sure that only available digits are used, and all of them are used. <lang MiniScript>evalAddSub = function()
result = evalMultDiv while true if not tokens then return result op = tokens[0] if op != "+" and op != "-" then return result tokens.pull // (discard operator) rhs = evalMultDiv if result == null or rhs == null then return null if op == "+" then result = result + rhs if op == "-" then result = result - rhs end while
end function
evalMultDiv = function()
result = evalAtom while true if not tokens then return result op = tokens[0] if op != "*" and op != "/" then return result tokens.pull // (discard operator) rhs = evalAtom if result == null or rhs == null then return null if op == "*" then result = result * rhs if op == "/" then result = result / rhs end while
end function
evalAtom = function()
if tokens[0] == "(" then tokens.pull result = evalAddSub if not tokens or tokens.pull != ")" then print "Unbalanced parantheses" return null end if return result end if num = val(tokens.pull) idx = availableDigits.indexOf(num) if idx == null then print str(num) + " is not available" return null else availableDigits.remove idx end if return num
end function
choices = [] for i in range(1, 4)
choices.push ceil(rnd*9)
end for result = null while result != 24
availableDigits = choices[0:] // (clones the list) print "Using only the digits " + availableDigits + "," tokens = input("enter an expression that comes to 24: ").replace(" ","").values result = evalAddSub if availableDigits then print "You forgot to use: " + availableDigits result = null end if if result != null then print "That equals " + result + "."
end while print "Great job!"</lang>
- Output:
Using only the digits [5, 5, 2, 7], enter an expression that comes to 24: (7+5)*2 You forgot to use: [5] Using only the digits [5, 5, 2, 7], enter an expression that comes to 24: 5*7-5*2 That equals 25. Using only the digits [5, 5, 2, 7], enter an expression that comes to 24: 5+5+7*2 That equals 24. Great job!
mIRC Scripting Language
<lang mirc>alias 24 {
dialog -m 24-Game 24-Game
}
dialog 24-Game {
title "24-Game" size -1 -1 100 70 option dbu text "", 1, 29 7 42 8 text "Equation", 2, 20 21 21 8 edit "", 3, 45 20 40 10 text "Status", 4, 10 34 80 8, center button "Calculate", 5, 5 45 40 20 button "New", 6, 57 47 35 15
}
on *:DIALOG:24-Game:init:*: {
did -o 24-Game 1 1 Numbers: $rand(1,9) $rand(1,9) $rand(1,9) $rand(1,9)
}
on *:DIALOG:24-Game:sclick:*: {
if ($did == 5) { if ($regex($did(3),/^[ (]*\d *[-+*/][ (]*\d[ ()]*[-+*/][ ()]*\d[ )]*[-+*/] *\d[ )]*$/)) && ($sorttok($regsubex($did(3),/[^\d]+/g,$chr(32)),32) == $sorttok($remove($did(1),Numbers:),32)) { did -o 24-Game 4 1 $iif($calc($did(3)) == 24,Correct,Wrong) } else { did -o 24-Game 4 1 Wrong Numbers or Syntax } } elseif ($did == 6) { did -o 24-Game 1 1 Numbers: $rand(1,9) $rand(1,9) $rand(1,9) $rand(1,9) }
}</lang>
Modula-2
<lang modula2>MODULE TwentyFour;
FROM InOut IMPORT WriteString, WriteLn, Write, ReadString, WriteInt; FROM RandomGenerator IMPORT Random;
TYPE operator_t = (add, sub, mul, div); expr_t = RECORD operand : ARRAY[0..3] OF CARDINAL; operator : ARRAY[1..3] OF operator_t; END;(*of RECORD*) numbers_t = SET OF CHAR;
VAR expr : expr_t; numbers : numbers_t; (*******************************************************************createExpr*) (*analyse the input string *) PROCEDURE createExpr(s: ARRAY OF CHAR);
VAR index, counter : INTEGER; token : CHAR; temp_expr : expr_t; operand : CARDINAL; operator : operator_t;
(************************************nextToken*) (* returns the next CHAR that isn`t a space *) PROCEDURE nextToken(): CHAR; BEGIN INC(index); WHILE (s[index] = ' ') DO INC(index); END;(*of WHILE*) RETURN(s[index]); END nextToken; (***********************************set_operand*) (* checks if the CHAR o inerhits a valid number*) (* and sets 'operand' to its value *) PROCEDURE set_operand(o: CHAR); BEGIN CASE o OF '0'..'9': IF o IN numbers THEN operand := ORD(o)-48; numbers := numbers - numbers_t{o}; ELSE WriteString("ERROR: '"); Write( o); WriteString( "' isn`t a available number "); WriteLn; HALT; END;(*of IF*)| 0 : WriteString("ERROR: error in input "); WriteLn; HALT; ELSE WriteString("ERROR: '"); Write( o); WriteString( "' isn`t a number "); WriteLn; HALT; END;(*of CASE*) END set_operand; (**********************************set_operator*) (* checks if the CHAR o inerhits a valid *) (* operator and sets 'operator' to its value *) PROCEDURE set_operator(o: CHAR); BEGIN CASE o OF '+' : operator := add;| '-' : operator := sub;| '*' : operator := mul;| '/' : operator := div;| 0 : WriteString("ERROR: error in input "); WriteLn; HALT; ELSE WriteString("ERROR: '"); Write( o); WriteString( "' isn`t a operator "); WriteLn; HALT; END;(*of CASE*) END set_operator; (************************************************) BEGIN index := -1;
token := nextToken(); set_operand(token); expr.operand[0] := operand;
token := nextToken(); set_operator(token); expr.operator[1] := operator;
token := nextToken();
set_operand(token);
expr.operand[1] := operand;
token := nextToken(); set_operator(token); expr.operator[2] := operator;
token := nextToken(); set_operand(token); expr.operand[2] := operand;
token := nextToken(); set_operator(token); expr.operator[3] := operator;
token := nextToken(); set_operand(token); expr.operand[3] := operand; END createExpr;
(*****************************************************************evaluateExpr*) (* evaluate the expresion that was createt by 'createExpr' *)
PROCEDURE evaluateExpr(VAR num: REAL);
VAR index : INTEGER; BEGIN WITH expr DO num := VAL(REAL,operand[0]); FOR index := 1 TO 3 DO CASE operator[index] OF add : num := num + VAL(REAL,operand[index]);| sub : num := num - VAL(REAL,operand[index]);| mul : num := num * VAL(REAL,operand[index]);| div : num := num / VAL(REAL,operand[index]); END;(*of CASE*) END;(*of FOR*) END;(*of WITH*) END evaluateExpr;
(**************************************************************generateNumbers*) (* generates the 4 random numbers ond write them *) PROCEDURE generateNumbers; VAR index,ran : INTEGER; BEGIN numbers := numbers_t{}; ran := Random(0,9); FOR index := 1 TO 4 DO WHILE (CHR(ran+48) IN numbers )DO ran := Random(0,9); END;(*of While*) Write(CHR(ran+48)); WriteLn; numbers := numbers + numbers_t{CHR(ran+48)} END;(*of FOR*) END generateNumbers; (****************************************************************Main Programm*) VAR str : ARRAY[0..255] OF CHAR; sum : REAL; BEGIN WriteString("Welcome to the 24 game in MODULA-2"); WriteLn; WriteString("Here are your numbers:"); WriteLn; generateNumbers; WriteString("Enter your equation(This implementation dosn`t support brackets yet): "); WriteLn; ReadString(str); createExpr(str); evaluateExpr(sum); WriteLn; WriteString("Result:"); WriteLn; WriteInt(TRUNC(sum),0); WriteLn; CASE (TRUNC(sum) - 24) OF 0 : WriteString("Perfect!");| 1 : WriteString("Almost perfect."); ELSE WriteString("You loose!"); END;(*of CASE*) WriteLn; END TwentyFour.</lang>
MUMPS
<lang mumps>24Game k number, operator, bracket ; generate 4 random numbers each between 1 & 9 ; duplicates allowed! s n1=$r(9)+1, n2=$r(9)+1, n3=$r(9)+1, n4=$r(9)+1 ; save a copy of them so that we can keep restarting ; if the user gets it wrong s s1=n1,s2=n2,s3=n3,s4=n4 Question s (numcount,opcount,lbrackcount,rbrackcount)=0 ; restart with the random numbers already found s n1=s1,n2=s2,n3=s3,n4=s4 w !,"Enter an arithmetic expression that evaluates to 24 using (", n1," ",n2," ",n3," ",n4,"): " r !,expr q:expr="" ; validate numbers and operators s error="" f n=1:1:$l(expr) { s char=$e(expr,n) if char?1n { s number($i(numcount))=char w ! zw char } elseif char?1(1"*",1"/",1"+",1"-") { s operator($i(opcount))=char } elseif char?1"(" { s bracket($i(lbrackcount))=char } elseif char?1")" { s bracket($i(rbrackcount))=char } else { s error="That ain't no character I wanted to see" q } } if error'="" w error g Question if numcount'=4 { w "Does not have 4 numbers, do it again." g Question } s error="" f n=1:1:4 { if number(n)=n1 { s n1="dont use again" continue } if number(n)=n2 { s n2="dont use again" continue } if number(n)=n3 { s n3="dont use again" continue } if number(n)=n4 { s n4="dont use again" continue } s error="Numbers entered do not match all of the randomly generated numbers." q } if error'="" { w error g Question } if opcount'=3 { w "Does not have 3 operators." g Question } if lbrackcount'=rbrackcount { w "brackets must be in pairs." g Question } x "s x="_expr if x'=24 { w !,"Answer does not = 24" g Question } w x q </lang>
Nanoquery
<lang Nanoquery>import Nanoquery.Lang import Nanoquery.Util
// a function to get the digits from an arithmetic expression def extract_digits(input) input = str(input) digits = {}
loc = 0 digit = "" while (loc < len(input)) if input[loc] in "0123456789" digit += input[loc] else if len(digit) > 0 digits.append(int(digit)) digit = "" end end loc += 1 end // check if there's a final digit if len(digit) > 0 digits.append(int(digit)) end
return digits end
// a function to duplicate a digit list def dup(list) nlist = {}
for n in list nlist.append(new(Integer, n)) end
return nlist end
// generate four random digits and output them random = new(Random) randDigits = {} for i in range(1, 4) randDigits.append(random.getInt(8) + 1) end println "Your digits are: " + randDigits + "\n"
// get expressions from the user until a valid one is found won = false while !won print "> " expr = input() tempDigits = dup(randDigits)
// check for invalid digits in the expression invalid = false digits = extract_digits(expr) for (i = 0) (!invalid and (i < len(digits))) (i += 1) if not digits[i] in tempDigits invalid = true println "Invalid digit " + digits[i] else tempDigits.remove(tempDigits) end end
// if there were no invalid digits, check if the expression // evaluates to 24 if !invalid a = null try exec("a = " + expr) catch println "Invalid expression " + expr end println a
if a = 24 println "Success!" won = true end end end</lang>
- Output:
Your digits are: [2, 5, 4, 6] > 2*5+(4*6) 34 > 2*4+5*6 38 > 5*6-(2*4) 22 > 5*6-(2+4) 24 Success!
Nim
<lang nim>from random import randomize, rand from strutils import Whitespace from algorithm import sort from sequtils import newSeqWith
randomize()
var
problem = newSeqWith(4, rand(1..9)) stack: seq[float] digits: seq[int]
echo "Make 24 with the digits: ", problem
template op(c: untyped) =
let a = stack.pop stack.add c(stack.pop, a)
for c in stdin.readLine:
case c of '1'..'9': digits.add c.ord - '0'.ord stack.add float(c.ord - '0'.ord) of '+': op `+` of '*': op `*` of '-': op `-` of '/': op `/` of Whitespace: discard else: raise newException(ValueError, "Wrong char: " & c)
sort digits sort problem if digits != problem:
raise newException(ValueError, "Not using the given digits.")
if stack.len != 1:
raise newException(ValueError, "Wrong expression.")
echo "Result: ", stack[0] echo if abs(stack[0] - 24) < 0.001: "Good job!" else: "Try again."</lang> Example game:
Make 24 with the digits: @[8, 1, 3, 1] 8 3 * 1 + 1 - Result: 24.0 Good job!
Nit
Source: the Nit’s official repository
<lang nit>redef class Char fun is_op: Bool do return "-+/*".has(self) end
- Get `numbers` and `operands` from string `operation` collect with `gets` in `main` function
- Fill `numbers` and `operands` array with previous extraction
fun exportation(operation: String, numbers: Array[Int], operands: Array[Char]) do var previous_char: nullable Char = null var number: nullable Int = null var negative = false
for i in operation.length.times do var current_char = operation[i] var current_int = current_char.to_i
if (previous_char == null or previous_char.is_op) and current_char == '-' then negative = true continue end
if current_char.is_digit then if number == null then number = current_int else number = number * 10 + current_int end end
if negative and (current_char.is_op or i == operation.length - 1) then number = number - number * 2 negative = false end
if (current_char.is_op or i == operation.length - 1) and number != null then numbers.add(number) number = null end
if not negative and current_char.is_op then operands.add(current_char) end previous_char = current_char end # Update `numbers` and `operands` array in main function with pointer end
- Create random numbers between 1 to 9
fun random: Array[Int] do return [for i in 4.times do 1 + 9.rand] end
- Make mathematical operation with `numbers` and `operands` and add the operation result into `random_numbers`
fun calculation(random_numbers, numbers: Array[Int], operands: Array[Char]) do var number = 0 var temp_numbers = numbers.clone
while temp_numbers.length > 1 do var operand = operands.shift var a = temp_numbers.shift var b = temp_numbers.shift
if operand == '+' then number = a + b if operand == '-' then number = a - b if operand == '*' then number = a * b if operand == '/' then number = a / b
temp_numbers.unshift(number) end if number != 0 then random_numbers.add(number) end
- Check if used `numbers` exist in the `random_numbers` created
fun numbers_exists(random_numbers, numbers: Array[Int]): Bool do for number in numbers do if not random_numbers.count(number) >= numbers.count(number) then return false end return true end
- Remove `numbers` when they are used
fun remove_numbers(random_numbers, numbers: Array[Int]) do for number in numbers do random_numbers.remove(number) end
- Check if the mathematical `operation` is valid
fun check(operation: String): Bool do var previous_char: nullable Char = null var next_char: nullable Char = null var next_1_char: nullable Char = null
for i in operation.length.times do var current_char = operation[i]
if i + 1 < operation.length then next_char = operation[i + 1] if i + 2 < operation.length then next_1_char = operation[i + 2] else next_1_char = null end else next_char = null end
if not current_char.is_op and not current_char.is_digit then return false if next_char == null and current_char.is_op then return false
if previous_char == null then if next_char == null or next_1_char == null then return false if current_char == '-' and not next_char.is_digit then return false if current_char != '-' and not current_char.is_digit then return false else if next_char != null then if previous_char.is_digit and current_char.is_op and not (next_char == '-' and next_1_char != null and next_1_char.is_digit or next_char.is_digit) then return false end end end previous_char = current_char end return true end
var random_numbers = new Array[Int] var operation = ""
random_numbers = random while not random_numbers.has(24) and random_numbers.length > 1 do var numbers = new Array[Int] var operands = new Array[Char]
print "numbers: " + random_numbers.join(", ") operation = gets if check(operation) then exportation(operation, numbers, operands) if numbers_exists(random_numbers, numbers) then calculation(random_numbers, numbers, operands) remove_numbers(random_numbers, numbers) else print "NUMBERS ERROR!" end else print "STRING ERROR!" end end
if random_numbers.has(24) then print "CONGRATULATIONS" else print "YOU LOSE"</lang>
Objeck
<lang objeck>use Collection.Generic; use System.Matrix;
class RPNParser {
@stk : Stack<IntHolder>; @digits : List<IntHolder>;
function : Main(args : String[]) ~ Nil { digits := List->New()<IntHolder>; "Make 24 with the digits: "->Print(); for(i := 0; i < 4; i += 1;) { n : Int := Int->Random(1, 9); " {$n}"->Print(); digits->AddBack(n); }; '\n'->Print();
parser := RPNParser->New(); if(parser->Parse(System.IO.Console->ReadString(), digits)) { result := parser->GetResult(); if(result = 24) { "Good job!"->PrintLine(); } else { "{$result}, Try again."->PrintLine(); }; } else { "Invalid sequence"->PrintLine(); }; }
New() { @stk := Stack->New()<IntHolder>; @digits := List->New()<IntHolder>; }
method : Op(f : \Func->Calc) ~ Nil { if(@stk->Size() < 2) { "Improperly written expression"->ErrorLine(); Runtime->Exit(1); }; b := @stk->Pop(); a := @stk->Pop(); @stk->Push(f(a, b)); }
method : Parse(c : Char) ~ Nil { if(c >= '0' & c <= '9') { value : Int := c - '0'; @stk->Push(value); @digits->AddBack(value); } else if(c = '+') { Op(\Func->Calc : (a, b) => a + b); } else if(c = '-') { Op(\Func->Calc : (a, b) => a - b); } else if(c = '*') { Op(\Func->Calc : (a, b) => a * b); } else if(c = '/') { Op(\Func->Calc : (a, b) => { if(b <> 0) { return a / b; } else { return 0; }; }); }; }
method : GetResult() ~ Int { if(@stk->Size() = 1) { return @stk->Top(); };
return 0; }
method : Parse(s : String, digits : List<IntHolder>) ~ Bool { each(i : s) { Parse(s->Get(i)); };
@digits->Rewind(); while(@digits->More()) { left := @digits->Get()->Get(); digits->Rewind(); found := false; while(digits->More() & found = false) { right := digits->Get()->Get(); if(left = right) { digits->Remove(); found := true; } else { digits->Next(); }; }; @digits->Next(); };
return digits->IsEmpty(); }
}
alias Func {
Calc : (IntHolder, IntHolder) ~ IntHolder
}</lang>
OCaml
Compile with:
ocamlopt -pp camlp4o g24.ml -o g24.opt
<lang ocaml>type expression =
| Const of float | Sum of expression * expression (* e1 + e2 *) | Diff of expression * expression (* e1 - e2 *) | Prod of expression * expression (* e1 * e2 *) | Quot of expression * expression (* e1 / e2 *)
let rec eval = function
| Const c -> c | Sum (f, g) -> eval f +. eval g | Diff(f, g) -> eval f -. eval g | Prod(f, g) -> eval f *. eval g | Quot(f, g) -> eval f /. eval g
let rec extract acc = function
| Const c -> (c::acc) | Sum (f, g) -> (extract acc f) @ (extract [] g) | Diff(f, g) -> (extract acc f) @ (extract [] g) | Prod(f, g) -> (extract acc f) @ (extract [] g) | Quot(f, g) -> (extract acc f) @ (extract [] g)
open Genlex
let lexer = make_lexer ["("; ")"; "+"; "-"; "*"; "/"]
let rec parse_expr = parser
[< e1 = parse_mult; e = parse_more_adds e1 >] -> e and parse_more_adds e1 = parser [< 'Kwd "+"; e2 = parse_mult; e = parse_more_adds (Sum(e1, e2)) >] -> e | [< 'Kwd "-"; e2 = parse_mult; e = parse_more_adds (Diff(e1, e2)) >] -> e | [< >] -> e1 and parse_mult = parser [< e1 = parse_simple; e = parse_more_mults e1 >] -> e and parse_more_mults e1 = parser [< 'Kwd "*"; e2 = parse_simple; e = parse_more_mults (Prod(e1, e2)) >] -> e | [< 'Kwd "/"; e2 = parse_simple; e = parse_more_mults (Quot(e1, e2)) >] -> e | [< >] -> e1 and parse_simple = parser | [< 'Int i >] -> Const(float i) | [< 'Float f >] -> Const f | [< 'Kwd "("; e = parse_expr; 'Kwd ")" >] -> e
let parse_expression = parser [< e = parse_expr; _ = Stream.empty >] -> e
let read_expression s = parse_expression(lexer(Stream.of_string s))
let () =
Random.self_init(); print_endline " The 24 Game
Given any four digits in the range 1 to 9, which may have repetitions, Using just the +, -, *, and / operators; and the possible use of brackets, (), show how to make an answer of 24.
An answer of 'q' will quit the game. An answer of '!' will generate a new set of four digits. Otherwise you are repeatedly asked for an expression until it evaluates to 24
Note: you cannot form multiple digit numbers from the supplied digits, so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed.\n";
let sort = List.sort compare in let digits = ref [] in let digit_set () = let ar = Array.init 4 (fun _ -> 1 + Random.int 9) in digits := Array.to_list(Array.map float_of_int ar); print_string "The four digits: "; List.iter (Printf.printf " %g") !digits; print_newline(); in
digit_set(); while true do print_string "Expression: "; let str = read_line() in if str = "q" then exit 0; if str = "!" then digit_set() else begin let expr = read_expression str in let res = eval expr in Printf.printf " = %g\n%!" res; if res = 24. && (sort !digits) = (sort (extract [] expr)) then (print_endline "Congratulations!"; digit_set()) else print_endline "Try again" end done</lang>
Oforth
<lang Oforth>import: mapping
- game
| l expr w n i |
4 #[ 9 rand ] Array init ->l System.Out "Digits : " << l << " --> RPN Expression for 24 : " << drop System.Console accept ->expr expr words forEach: w [ w "+" == ifTrue: [ + continue ] w "-" == ifTrue: [ - continue ] w "*" == ifTrue: [ * continue ] w "/" == ifTrue: [ >float / continue ] w >integer dup ->n ifNull: [ System.Out "Word " << w << " not allowed " << cr break ] n l indexOf dup ->i ifNull: [ System.Out "Integer " << n << " is wrong " << cr break ] n l put(i, null) ] #null? l conform? ifFalse: [ "Sorry, all numbers must be used..." . return ] 24 if=: [ "You won !" ] else: [ "You loose..." ] .
- </lang>
ooRexx
While the solution shown within this page at Rexx version 2 was created for Classic Rexx it also can be used unchanged by the ooRexx interpreter and so can be considered a solution for the ooRexx language too.
Incompatibilities(*) that were originally in Rexx version 1 were meanwhile "fixed", so it also can be used unchanged by the ooRexx interpreter and so can be considered a solution for the ooRexx language too.
(*) Classic Rexx accepts assignment without an expression (x=;), ooRexx does not.
OpenEdge/Progress
The dynamic query parser is used to evaluate the expression. <lang Progress (OpenEdge ABL)>DEFINE TEMP-TABLE tt NO-UNDO FIELD ii AS INTEGER.
DEFINE VARIABLE p_deanswer AS DECIMAL NO-UNDO. DEFINE VARIABLE idigits AS INTEGER NO-UNDO EXTENT 4. DEFINE VARIABLE ii AS INTEGER NO-UNDO. DEFINE VARIABLE Digits AS CHARACTER NO-UNDO FORMAT "x(7)". DEFINE VARIABLE Answer AS CHARACTER NO-UNDO FORMAT "x(7)". DEFINE VARIABLE cexpression AS CHARACTER NO-UNDO. DEFINE VARIABLE cmessage AS CHARACTER NO-UNDO. DEFINE VARIABLE cchar AS CHARACTER NO-UNDO.
FUNCTION calculate RETURNS LOGICAL (
i_de AS DECIMAL
):
p_deanswer = i_de.
END FUNCTION.
/* generate problem */ DO ii = 1 TO 4:
ASSIGN idigits [ii] = RANDOM( 1, 9 ). Digits = Digits + STRING( idigits [ii] ) + " " .
END.
/* ui */ DISPLAY Digits. UPDATE Answer.
/* check valid input */ DO ii = 1 TO 7:
cchar = SUBSTRING( Answer, ii, 1 ). IF cchar > "" THEN DO: IF ii MODULO 2 = 1 THEN DO: IF LOOKUP( cchar, Digits, " " ) = 0 THEN cmessage = cmessage + SUBSTITUTE( "Invalid digit: &1.~r", cchar ). ELSE ENTRY( LOOKUP( cchar, Digits, " " ), Digits, " " ) = "". END. ELSE DO: IF LOOKUP( cchar, "+,-,/,*" ) = 0 THEN cmessage = cmessage + SUBSTITUTE( "&1 is not a valid operator.~r", cchar ). END. END.
END. IF TRIM( Digits ) > "" THEN
cmessage = cmessage + SUBSTITUTE( "You did not use digits: &1":U, TRIM( Digits ) ).
IF cmessage = "" THEN DO:
/* expressions need spacing */ DO ii = 1 TO 7: cexpression = cexpression + SUBSTRING( Answer, ii, 1 ) + " ". END. /* use dynamic query to parse expression */ TEMP-TABLE tt:DEFAULT-BUFFER-HANDLE:FIND-FIRST( SUBSTITUTE( "WHERE NOT DYNAMIC-FUNCTION( 'calculate', DECIMAL( &1 ) )", cexpression ) ) NO-ERROR. IF p_deanswer <> 24 THEN cmessage = cmessage + SUBSTITUTE( "The expression evaluates to &1.", p_deanswer ). ELSE cmessage = "Solved!".
END.
MESSAGE cmessage VIEW-AS ALERT-BOX. </lang>
PARI/GP
<lang parigp>game()={
my(v=vecsort(vector(4,i,random(8)+1))); print("Form 24 using */+-() and: "v); while(1, my(ans=input); if (!valid(s,v), next); trap(, print("Arithmetic error"); next , if(eval(s)==24, break, print("Bad sum")) ) ); print("You win!")
}; valid(s,v)={
my(op=vecsort(Vec("+-*/()")),u=[]); s=Vec(s); for(i=1,#s, if(setsearch(op,s[i]),next); trap(, print("Invalid character "s[i]); return(0) , if(setsearch(v,eval(s[i])), u=concat(u,eval(s[i])) , print(s[i]" not allowed"); return(0) ) ) ); for(i=2,#s, if(!setsearch(op,s[i])&!setsearch(op,s[i-1]), print("Concatenating digits is not allowed!"); return(0) ) ); if(vecsort(u)!=v, print("Invalid digits"); 0 , 1 )
};</lang>
Perl
<lang perl>#!/usr/bin/env perl use warnings; use strict; use feature 'say';
print <<'EOF'; The 24 Game
Given any four digits in the range 1 to 9, which may have repetitions, Using just the +, -, *, and / operators; and the possible use of parentheses, (), show how to make an answer of 24.
An answer of "q" or EOF will quit the game. A blank answer will generate a new set of four digits. Otherwise you are repeatedly asked for an expression until it evaluates to 24.
Note: you cannot form multiple digit numbers from the supplied digits, so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed. EOF
my $try = 1; while (1) {
my @digits = map { 1+int(rand(9)) } 1..4; say "\nYour four digits: ", join(" ", @digits); print "Expression (try ", $try++, "): ";
my $entry = <>; if (!defined $entry || $entry eq 'q') { say "Goodbye. Sorry you couldn't win."; last; } $entry =~ s/\s+//g; # remove all white space next if $entry eq ;
my $given_digits = join "", sort @digits; my $entry_digits = join "", sort grep { /\d/ } split(//, $entry); if ($given_digits ne $entry_digits || # not correct digits $entry =~ /\d\d/ || # combined digits $entry =~ m|[-+*/]{2}| || # combined operators $entry =~ tr|-0-9()+*/||c) # Invalid characters { say "That's not valid"; next; }
my $n = eval $entry;
if (!defined $n) { say "Invalid expression"; } elsif ($n == 24) { say "You win!"; last; } else { say "Sorry, your expression is $n, not 24"; }
}</lang>
Phix
-- Note this uses simple/strict left association, so for example: -- 1+2*1*8 is ((1+2)*1)*8 not 1+((2*1)*8) [or 1+(2*(1*8))], and -- 7-(2*2)*8 is (7-(2*2))*8 not 7-((2*2)*8) -- Does not allow unary minus on the first digit. -- Uses solve24() from the next task, when it can. -- (you may want to comment out the last 2 lines/uncomment the if 0, in that file) -- --include 24_game_solve.exw --with trace forward function eval(string equation, sequence unused, integer idx=1) -- (the above definition is entirely optional, but good coding style) constant errorcodes = {"digit expected", -- 1 "')' expected", -- 2 "digit already used", -- 3 "digit not offered", -- 4 "operand expected"} -- 5 function card(integer idx) -- (for error handling) if idx=1 then return "1st" end if if idx=2 then return "2nd" end if -- (assumes expression is less than 21 characters) return sprintf("%dth",idx) end function function errorchar(sequence equation, integer idx) if idx>length(equation) then return "" end if return sprintf("(%s)",equation[idx]) end function sequence rset = repeat(0,4) procedure new_rset() for i=1 to length(rset) do rset[i] = rand(9) end for end procedure function get_operand(string equation, integer idx, sequence unused) integer error = 1 -- "digit expected" atom res if idx<=length(equation) then integer ch = equation[idx] if ch='(' then {error,res,unused,idx} = eval(equation,unused,idx+1) if error=0 and idx<=length(equation) then ch = equation[idx] if ch=')' then return {0,res,unused,idx+1} end if end if if error=0 then error = 2 -- "')' expected" end if elsif ch>='0' and ch<='9' then res = ch-'0' integer k = find(res,unused) if k!=0 then unused[k..k] = {} return {0,res,unused,idx+1} end if if find(res,rset) then error = 3 -- "digit already used" else error = 4 -- "digit not offered" end if end if end if return {error,0,unused,idx} end function function get_operator(string equation, integer idx) integer error = 5 -- "operand expected" if idx<=length(equation) then integer ch = equation[idx] if find(ch,"+-/*") then return {0,ch,idx+1} end if end if return {error,0,idx} end function function eval(string equation, sequence unused, integer idx=1) atom lhs, rhs integer ch, error {error,lhs,unused,idx} = get_operand(equation,idx,unused) if error=0 then while 1 do {error,ch,idx} = get_operator(equation,idx) if error!=0 then exit end if {error,rhs,unused,idx} = get_operand(equation,idx,unused) if error!=0 then exit end if if ch='+' then lhs += rhs elsif ch='-' then lhs -= rhs elsif ch='/' then lhs /= rhs elsif ch='*' then lhs *= rhs else ?9/0 -- (should not happen) end if if idx>length(equation) then return {0,lhs,unused,idx} end if ch = equation[idx] if ch=')' then return {0,lhs,unused,idx} end if end while end if return {error,0,unused,idx} end function function strip(string equation) for i=length(equation) to 1 by -1 do if find(equation[i]," \t\r\n") then equation[i..i] = "" end if end for return equation end function function strip0(atom a) -- (for error handling) string res = sprintf("%f",a) for i=length(res) to 2 by -1 do integer ch = res[i] if ch='.' then return res[1..i-1] end if if ch!='0' then return res[1..i] end if end for return res end function procedure play() sequence unused string equation integer error,idx atom res new_rset() printf(1,"Enter an expression which evaluates to exactly 24\n"& "Use all of, and only, the digits %d, %d, %d, and %d\n"& "You may only use the operators + - * /\n"& "Parentheses and spaces are allowed\n",rset) while 1 do equation = strip(gets(0)) if upper(equation)="Q" then exit end if if equation="?" then puts(1,"\n") integer r_solve24 = routine_id("solve24") -- see below if r_solve24=-1 then -- (someone copied just this code out?) puts(1,"no solve24 routine\n") else call_proc(r_solve24,{rset}) end if else {error,res,unused,idx} = eval(equation, rset) if error!=0 then printf(1," %s on the %s character%s\n",{errorcodes[error],card(idx),errorchar(equation,idx)}) elsif idx<=length(equation) then printf(1,"\neval() returned only having processed %d of %d characters\n",{idx,length(equation)}) elsif length(unused) then printf(1," not all the digits were used\n",error) elsif res!=24 then printf(1,"\nresult is %s, not 24\n",{strip0(res)}) else puts(1," correct! Press any key to quit\n") {} = wait_key() exit end if end if puts(1,"enter Q to give up and quit\n") end while end procedure play()
PHP
<lang PHP>#!/usr/bin/env php The 24 Game
Given any four digits in the range 1 to 9, which may have repetitions, Using just the +, -, *, and / operators; and the possible use of brackets, (), show how to make an answer of 24.
An answer of "q" will quit the game. An answer of "!" will generate a new set of four digits. Otherwise you are repeatedly asked for an expression until it evaluates to 24
Note: you cannot form multiple digit numbers from the supplied digits, so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed.
<?php
while (true) {
$numbers = make_numbers();
for ($iteration_num = 1; ; $iteration_num++) { echo "Expresion $iteration_num: ";
$entry = rtrim(fgets(STDIN));
if ($entry === '!') break; if ($entry === 'q') exit;
$result = play($numbers, $entry);
if ($result === null) { echo "That's not valid\n"; continue; } elseif ($result != 24) { echo "Sorry, that's $result\n"; continue; } else { echo "That's right! 24!!\n"; exit; } }
}
function make_numbers() {
$numbers = array();
echo "Your four digits: ";
for ($i = 0; $i < 4; $i++) { $number = rand(1, 9); // The check is needed to avoid E_NOTICE from PHP if (!isset($numbers[$number])) { $numbers[$number] = 0; } $numbers[$number]++; print "$number "; }
print "\n";
return $numbers;
}
function play($numbers, $expression) {
$operator = true; for ($i = 0, $length = strlen($expression); $i < $length; $i++) { $character = $expression[$i];
if (in_array($character, array('(', ')', ' ', "\t"))) continue;
$operator = !$operator;
if (!$operator) { if (!empty($numbers[$character])) { $numbers[$character]--; continue; } return; } elseif (!in_array($character, array('+', '-', '*', '/'))) { return; } }
foreach ($numbers as $remaining) { if ($remaining > 0) { return; } } return eval("return $expression;");
} ?></lang>
PicoLisp
<lang PicoLisp> (load "@lib/frac.l")
(de random4digits ()
(setq Numbers (make (do 4 (link (rand 1 9))))) Numbers )
(de prompt ()
(prinl "^JPlease enter a 'Lisp' expression (integer or fractional math) that equals 24,^J" "using (, ), frac, + or f+, - or f-, * or f*, / or f/, and " Numbers "^J" "(use each number only once). Enter . to quit." ) )
(de getinput ()
(setq Expression (catch ’NIL (in NIL (read)))) Expression )
(de checkexpression (Numbers Expression)
(make (when (diff Numbers (fish num? Expression)) (link "Not all numbers used.") ) (when (diff (fish num? Expression) Numbers) (link "Using wrong number(s).")) (if (sub? "f" (pack Expression)) (when (diff (fish sym? Expression) '(frac f+ f- f* f/)) (link "Illegal operator(s). If fractional expression, must use frac, f+, f-, f*, f/ only.") ) (when (diff (fish sym? Expression) '(+ - * /)) (link "Using illegal operator(s).") ) ) ) )
(de instructions ()
(prinl "Example 'Lisp' expression: (- (* 3 9) (+ 1 2))") (prinl "Example 'Lisp' fractional expression:^J" "(f- (f* (frac 3 1)(frac 9 1)) (f+ (frac 1 1)(frac 2 1)))" ) (prinl "Use a fractional expression 'just for fun (as above)' OR if your solution^J" "would lose remainder value(s) otherwise (through integer division)." ) )
(de loopuntilquit ()
(instructions) (loop (set 'Numbers (random4digits)) (prompt) (set 'Expression (getinput)) (if (= Expression ".") (prog (prinl "bye!") (bye))) (set 'Check (checkexpression Numbers Expression)) (if (car Check) (mapcar prinl Check) (prog (set 'Evaluated (eval Expression)) (if (or (= Evaluated 24) (= Evaluated (24 . 1))) (prinl "Congratulations!") (prinl "That evaluated to " Evaluated " Try again!") ) ) ) ) )
(loopuntilquit)
</lang>
- Output:
pil 24game.l + Example 'Lisp' expression: (+ (* 4 5) (- 1 2)) Example 'Lisp' fractional expression: (f+ (f* (frac 4 1)(frac 5 1)) (f- (frac 1 1)(frac 2 1))) Use a fractional expression if your solution would lose remainder value(s) otherwise. Please enter a 'Lisp' expression (regular or fractional math style) that equals 24, using (, ), frac, + or f+, - or f-, * or f*, / or f/, and 1329. Enter . to quit. (f- (f* (frac 3 1)(frac 9 1)) (f+ (frac 1 1)(frac 2 1))) Congratulations! Please enter a 'Lisp' expression (regular or fractional math style) that equals 24, using (, ), frac, + or f+, - or f-, * or f*, / or f/, and 3758. Enter . to quit. (+ (* (- 8 5) 7) 3) Congratulations! Please enter a 'Lisp' expression (regular or fractional math style) that equals 24, using (, ), frac, + or f+, - or f-, * or f*, / or f/, and 3758. Enter . to quit. (f- (f* (frac 3 1)(frac 7 1)) (+ (frac 5 1)(frac 8 1))) Using wrong number(s). Illegal operator(s). If fractional expression, must use frac, f+, f-, f*, f/ only. Please enter a 'Lisp' expression (regular or fractional math style) that equals 24, using (, ), frac, + or f+, - or f-, * or f*, / or f/, and 2713. Enter . to quit. (^ 2 7 1 3) Using illegal operator(s). Please enter a 'Lisp' expression (regular or fractional math style) that equals 24, using (, ), frac, + or f+, - or f-, * or f*, / or f/, and 8367. Enter . to quit. (+ 8 3 6) Not all numbers used. Please enter a 'Lisp' expression (regular or fractional math style) that equals 24, using (, ), frac, + or f+, - or f-, * or f*, / or f/, and 1635. Enter . to quit. . bye!
PL/I
<lang pli> /* Plays the game of 24. */
TWENTYFOUR: procedure options (main); /* 14 August 2010 */
CTP: procedure (E) returns (character(50) varying);
declare E character (*) varying; declare OUT character (length(E)) varying; declare S character (length(E)) varying controlled; declare c character (1); declare i fixed binary;
/* This procedure converts an arithmetic expression to Reverse Polish Form. */ /* A push-down pop-up stack is used for operators. */ priority: procedure (a) returns (fixed decimal (1));
declare a character (1); declare ops character (10) initial ('#+-*/') varying static; declare pri(6) fixed decimal (1) initial (1,2,2,3,3,4) static; declare i fixed binary;
i = index(ops,a); return (pri(i));
end priority;
allocate S; S = '#'; out = ; do i = 1 to length(E); c = substr(E, i, 1); if index('+-*/', c) > 0 then do; /* Copy any higher priority operators on the stack to the output. */ do while ( priority(c) <= priority((S)) ); out = out || S; free S; end; /* Copy the input character to the stack. */ allocate S; S = c; end;
if index('123456789', c) > 0 then out = out || c; end; do while (allocation(S) > 1); out = out || s; free S; end; return (out);
end CTP;
/* Given a push-down pop-up stack, and an expresion in */ /* Reverse Polish notation, evaluate the expression. */ EVAL: procedure (E) returns (fixed decimal(15));
declare E character (*) varying; declare S fixed decimal (15) controlled; declare (a, b) fixed decimal (15); declare c character (1); declare p fixed binary; declare (empty_stack, invalid_expression) condition;
on condition (empty_stack) begin; put skip list ('Your expression is not valid.'); stop; end; on condition (invalid_expression) begin; put skip list ('Your expression is not valid.'); stop; end;
do p = 1 to length(E); c = substr(E, p, 1); if index('123456789', c) > 0 then do; allocate S; S = c; end; else do; if allocation(S) = 0 then signal condition (empty_stack); b = S; free S; if allocation(S) = 0 then signal condition (empty_stack); a = S; select (c); when ('+') S = a + b; when ('-') S = a - b; when ('*') S = a * b; when ('/') S = a / b; when ('^') S = a ** b; otherwise signal condition (invalid_expression); end; end; end; if allocation(S) ^= 1 then signal condition (invalid_expression); return (S);
END eval;
/* Check that the player has used every digit and no others. */ VALIDATE: procedure (E);
declare E character (*) varying; declare E2 character (length(E)), (i, j) fixed binary; declare digits(9) character (1) static initial ('1', '2', '3', '4', '5', '6', '7', '8', '9');
E2 = translate(E, ' ', '+-*/' ); do i = 1 to 4; j = index(E2, digits(k(i))); if j > 0 then substr(E2, j, 1) = ' '; else do; put skip list ('You must use the digits supplied.'); stop; end; end; if E2 ^= then do; put skip list ('You must use every digit supplied, and no others.'); stop; end;
end VALIDATE;
declare E character (40) varying; declare k(4) fixed decimal; declare (time, random) builtin; declare V fixed decimal (15);
k = random(TIME); k = 9*random() + 1; put skip edit ('Here are four integers:', k) (a); put skip list ('With these integers, make up an arithmetic expression' || ' that evaluates to 24.'); put skip list ('You can use any of the operators +, -, *, and /'); put skip list ('E.g., Given the integers 1, 3, 7, and 6,' || ' the expression 6*3+7-1 evaluates to 24.');
put skip list ('Please type an arithmetic expression :'); get edit (E) (L) COPY;
CALL VALIDATE (E); /* Check that the player has used every digit and no others. */
E = CTP(E); V = EVAL (E); if V = 24 then put skip list ('Congratulations: the expression evaluates to 24.'); else put skip edit ('The result is ', trim(V), ' which is not correct') (a);
end TWENTYFOUR; </lang>
Potion
<lang Potion>is_num = (s):
x = s ord(0) if (x >= "0"ord && x <= "9"ord): true. else: false. .
nums = (s):
res = () 0 to (s length, (b): c = s(b) if (is_num(c)): res push(c). .) res.
try = 1 while (true):
r = rand string digits = (r(0),r(1),r(2),r(3)) "\nMy next four digits: " print digits join(" ") say digit_s = digits ins_sort string
("Your expression to create 24 (try ", try, "): ") print entry = read slice(0,-1) expr = entry eval parse = nums(entry) parse_s = parse clone ins_sort string try++ if (parse length != 4): ("Wrong number of digits:", parse) say. elsif (parse_s != digit_s): ("Wrong digits:", parse) say. elsif (expr == 24): "You won!" say entry print, " => 24" say return(). else: (entry, " => ", expr string, " != 24") join("") say.
.</lang>
PowerShell
The "isNumeric" function was taken from the "Determine_if_a_string_is_numeric" task.
todo: add a validation that all given digits were used. Right now the validation is that 4 digits should be used in the expression, but not exactly the ones given. (example: if you are given the digits 2, 2, 6, 9 this program accepts the following solution: 6 * 4 * 2 / 2)
<lang powershell> CLS
Function isNumeric ($x) {
$x2 = 0 $isNum = [System.Int32]::TryParse($x,[ref]$x2)
Return $isNum }
$NumberArray = @() While( $NumberArray.Count -lt 4 ){
$NumberArray += Random -Minimum 1 -Maximum 10
}
Write-Host @" Welcome to the 24 game!
Here are your numbers: $($NumberArray -join ","). Use division, multiplication, subtraction and addition to get 24 as a result with these 4 numbers. "@
Do { $Wrong = 0 $EndResult = $null $TempChar = $null $TempChar2 = $null $Count = $null
$AllowableCharacters = $NumberArray + "+-*/()".ToCharArray()
$Result = Read-Host Foreach($Char in $Result.ToCharArray()) { If( $AllowableCharacters -notcontains $Char ){ $Wrong = 1 } }
If($Wrong -eq 1) { Write-Warning "Wrong input! Please use only the given numbers." } Foreach($Char in $Result.ToCharArray()) { If((IsNumeric $TempChar) -AND (IsNumeric $Char)) { Write-Warning "Wrong input! Combining two or more numbers together is not allowed!" } $TempChar = $Char } Foreach($Char in $Result.ToCharArray()) { If(IsNumeric $Char) { $Count++ } } If($Count -eq 4) { $EndResult = Invoke-Expression $Result If($EndResult -eq 24) { Write-Host "`nYou've won the game!" } Else { Write-Host "`n$EndResult is not 24! Too bad." } } Else { Write-Warning "Wrong input! You did not supply four numbers." }
} While($EndResult -ne 24) </lang>
ProDOS
This example uses the math module: <lang ProDOS>:a editvar /modify -random- = <10 printline These are your four digits: -random- -random- -random- -random- printline Use an algorithm to make the number 24. editvar /newvar /value=a /userinput=1 /title=Algorithm: do -a- if -a- /hasvalue 24 printline Your algorithm worked! & goto :b ( ) else printline Your algorithm did not work.
- b
editvar /newvar /value=b /userinput=1 /title=Do you want to play again? if -b- /hasvalue y goto :a else exitcurrentprogram</lang>
Prolog
<lang prolog>:- initialization(main).
answer(24).
play :- round, play ; true.
round :-
prompt(Ns), get_line(Input), Input \= "stop" , ( phrase(parse(Ns,[]), Input) -> Result = 'correct' ; Result = 'wrong' ), write(Result), nl, nl . % where prompt(Ns) :- length(Ns,4), maplist(random(1,10), Ns) , write('Digits: '), write(Ns), nl .
parse([],[X]) --> { answer(X) }. parse(Ns,[Y,X|S]) --> "+", { Z is X + Y }, parse(Ns,[Z|S]). parse(Ns,[Y,X|S]) --> "-", { Z is X - Y }, parse(Ns,[Z|S]). parse(Ns,[Y,X|S]) --> "*", { Z is X * Y }, parse(Ns,[Z|S]). parse(Ns,[Y,X|S]) --> "/", { Z is X div Y }, parse(Ns,[Z|S]). parse(Ns,Stack) --> " ", parse(Ns,Stack). parse(Ns,Stack) --> { select(N,Ns,Ns1), number_codes(N,[Code]) }
, [Code], parse(Ns1,[N|Stack]) .
get_line(Xs) :- get_code(X)
, ( X == 10 -> Xs = [] ; Xs = [X|Ys], get_line(Ys) ) .
main :- randomize, play, halt.</lang> Example "session":
Digits: [9,4,6,9] 46*9-9+ correct Digits: [7,4,7,8] 8 4 7 7 / - * correct Digits: [7,2,8,2] 7282--- wrong Digits: [2,6,7,1] 4611*** wrong Digits: [3,6,5,8] + wrong Digits: [2,1,7,7] stop
PureBasic
<lang PureBasic>#digitCount = 4 Global Dim digits(#digitCount - 1) ;holds random digits
Procedure showDigits()
Print(#CRLF$ + "These are your four digits: ") Protected i For i = 0 To #digitCount - 1 Print(Str(digits(i))) If i < (#digitCount - 1) Print(", ") Else PrintN("") EndIf Next Print("24 = ")
EndProcedure
Procedure playAgain()
Protected answer.s Repeat Print("Play again (y/n)? ") answer = LCase(Left(Trim(Input()), 1)) Select answer Case "n" ProcedureReturn #False Case "y" ProcedureReturn #True Default PrintN("") Continue EndSelect ForEver
EndProcedure
Procedure allDigitsUsed()
Protected i For i = 0 To #digitCount - 1 If digits(i) <> 0 ProcedureReturn #False EndIf Next ProcedureReturn #True
EndProcedure
Procedure isValidDigit(d)
For i = 0 To #digitCount - 1 If digits(i) = d digits(i) = 0 ProcedureReturn #True EndIf Next ProcedureReturn #False
EndProcedure
Procedure doOperation(List op.c(), List operand.f())
Protected x.f, y.f, op.c op = op(): DeleteElement(op()) If op = '(' ProcedureReturn #False ;end of sub-expression EndIf y = operand(): DeleteElement(operand()) x = operand() Select op Case '+' x + y Case '-' x - y Case '*' x * y Case '/' x / y EndSelect operand() = x ProcedureReturn #True ;operation completed
EndProcedure
- returns error if present and the expression results in *result\f
Procedure.s parseExpression(expr.s, *result.Float)
NewList op.c() NewList operand.f() expr = ReplaceString(expr, " ", "") ;remove spaces If Len(expr) = 0: *result\f = 0: ProcedureReturn "": EndIf ;no expression, return zero Protected *ech.Character = @expr, lastWasDigit, lastWasOper, parenCheck, c.c While *ech\c c = *ech\c Select c Case '*', '/', '-', '+' If Not lastWasDigit: ProcedureReturn "Improper syntax, need a digit between operators.": EndIf If ListSize(op()) And (FindString("*/", Chr(op()), 1) Or (FindString("+-", Chr(op()), 1) And FindString("+-", Chr(c), 1))) doOperation(op(), operand()) EndIf AddElement(op()): op() = c lastWasOper = #True: lastWasDigit = #False Case '(' If lastWasDigit: ProcedureReturn "Improper syntax, need an operator before left paren.": EndIf AddElement(op()): op() = c parenCheck + 1: lastWasOper = #False Case ')' parenCheck - 1: If parenCheck < 0: ProcedureReturn "Improper syntax, missing a left paren.": EndIf If Not lastWasDigit: ProcedureReturn "Improper syntax, missing a digit before right paren.": EndIf Repeat: Until Not doOperation(op(),operand()) lastWasDigit = #True Case '1' To '9' If lastWasDigit: ProcedureReturn "Improper syntax, need an operator between digits.": EndIf AddElement(operand()): operand() = c - '0' If Not isValidDigit(operand()): ProcedureReturn "'" + Chr(c) + "' is not a valid digit.": EndIf lastWasDigit = #True: lastWasOper = #False Default ProcedureReturn "'" + Chr(c) + "' is not allowed in the expression." EndSelect *ech + SizeOf(Character) Wend If parenCheck <> 0 Or lastWasOper: ProcedureReturn "Improper syntax, missing a right paren or digit.": EndIf Repeat If Not ListSize(op()): Break: EndIf Until Not doOperation(op(),operand()) *result\f = operand() ProcedureReturn "" ;no error
EndProcedure
Define success, failure, result.f, error.s, i If OpenConsole()
PrintN("The 24 Game" + #CRLF$) PrintN("Given four digits and using just the +, -, *, and / operators; and the") PrintN("possible use of brackets, (), enter an expression that equates to 24.") Repeat For i = 0 To #digitCount - 1 digits(i) = 1 + Random(8) Next showDigits() error = parseExpression(Input(), @result) If error = "" If Not allDigitsUsed() PrintN( "Wrong! (you didn't use all digits)"): failure + 1 ElseIf result = 24.0 PrintN("Correct!"): success + 1 Else Print("Wrong! (you got ") If result <> Int(result) PrintN(StrF(result, 2) + ")") Else PrintN(Str(result) + ")") EndIf failure + 1 EndIf Else PrintN(error): failure + 1 EndIf Until Not playAgain() PrintN("success:" + Str(success) + " failure:" + Str(failure) + " total:" + Str(success + failure)) Print(#CRLF$ + "Press ENTER to exit"): Input() CloseConsole()
EndIf</lang>
- Output:
The 24 Game Given four digits and using just the +, -, *, and / operators; and the possible use of brackets, (), enter an expression that equates to 24. These are your four digits: 9, 2, 8, 7 24 = 9*8/2-7 Wrong! (you got 29) Play again (y/n)? y These are your four digits: 5, 5, 5, 6 24 = 5*5+5-6 Correct! Play again (y/n)? n success:1 failure:1 total:2
Python
Python: Original, with output
Uses eval, the built-in expression evaluator of infix expressions. <lang python>
The 24 Game
Given any four digits in the range 1 to 9, which may have repetitions, Using just the +, -, *, and / operators; and the possible use of brackets, (), show how to make an answer of 24.
An answer of "q" will quit the game. An answer of "!" will generate a new set of four digits. Otherwise you are repeatedly asked for an expression until it evaluates to 24
Note: you cannot form multiple digit numbers from the supplied digits, so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed.
from __future__ import division, print_function import random, ast, re import sys
if sys.version_info[0] < 3: input = raw_input
def choose4():
'four random digits >0 as characters' return [str(random.randint(1,9)) for i in range(4)]
def welcome(digits):
print (__doc__) print ("Your four digits: " + ' '.join(digits))
def check(answer, digits):
allowed = set('() +-*/\t'+.join(digits)) ok = all(ch in allowed for ch in answer) and \ all(digits.count(dig) == answer.count(dig) for dig in set(digits)) \ and not re.search('\d\d', answer) if ok: try: ast.parse(answer) except: ok = False return ok
def main():
digits = choose4() welcome(digits) trial = 0 answer = chk = ans = False while not (chk and ans == 24): trial +=1 answer = input("Expression %i: " % trial) chk = check(answer, digits) if answer.lower() == 'q': break if answer == '!': digits = choose4() print ("New digits:", ' '.join(digits)) continue if not chk: print ("The input '%s' was wonky!" % answer) else: ans = eval(answer) print (" = ", ans) if ans == 24: print ("Thats right!") print ("Thank you and goodbye")
if __name__ == '__main__': main() </lang>
- Output:
The 24 Game Given any four digits in the range 1 to 9, which may have repetitions, Using just the +, -, *, and / operators; and the possible use of brackets, (), show how to make an answer of 24. An answer of "q" will quit the game. An answer of "!" will generate a new set of four digits. Note: you cannot form multiple digit numbers from the supplied digits, so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed. Your four digits: 3 2 4 6 Expression 1: (3 - 1)*(6*4) The input '(3 - 1)*(6*4)' was wonky! Expression 2: (3 - 2) * 6 * 4 = 24 That's right! Thank you and goodbye.
Python: Alternative
<lang python>import random, re chars = ["(",")","/","+","-","*"] while True:
charsandints, ints = [], [] for x in range(4): ints.append(str(random.randrange(1,10))) charsandints = chars + ints print "Numbers are:", ints guess = raw_input("Enter your guess:") if guess.lower() == "q": break elif guess.lower() == "|": pass else: flag = True for a in guess: if a not in charsandints or guess.count(a) > charsandints.count(a): flag = False if re.search("\d\d", guess): print "You cannot combine digits." break if flag: print "Your result is: ", eval(guess) if eval(guess) == 24: print "You won" break else: print "You lost" break else: print "You cannot use anthing other than", charsandints break
print "Thanks for playing"</lang>
R
This makes use of R's metaprogramming (parse, eval, etc.). It uses parse to obtain a parse tree, which is scanned for containing only permitted elements before evaluating.
<lang r>twenty.four <- function(operators=c("+", "-", "*", "/", "("),
selector=function() sample(1:9, 4, replace=TRUE), arguments=selector(), goal=24) { newdigits <- function() { arguments <<- selector() cat("New digits:", paste(arguments, collapse=", "), "\n") } help <- function() cat("Make", goal, "out of the numbers",paste(arguments, collapse=", "), "and the operators",paste(operators, collapse=", "), ".", "\nEnter 'q' to quit, '!' to select new digits,", "or '?' to repeat this message.\n") help() repeat { switch(input <- readline(prompt="> "), q={ cat("Goodbye!\n"); break }, `?`=help(), `!`=newdigits(), tryCatch({ expr <- parse(text=input, n=1)1 check.call(expr, operators, arguments) result <- eval(expr) if (isTRUE(all.equal(result, goal))) { cat("Correct!\n") newdigits() } else { cat("Evaluated to", result, "( goal", goal, ")\n") } },error=function(e) cat(e$message, "\n"))) }
}
check.call <- function(expr, operators, arguments) {
unexpr <- function(x) { if (is.call(x)) unexpr(as.list(x)) else if (is.list(x)) lapply(x,unexpr) else x } leaves <- unlist(unexpr(expr)) if (any(disallowed <- !leaves %in% c(lapply(operators, as.name), as.list(arguments)))) { stop("'", paste(sapply(leaves[disallowed], as.character), collapse=", "), "' not allowed. ") } numbers.used <- unlist(leaves[sapply(leaves, mode) == 'numeric']) if (! isTRUE(all.equal(sort(numbers.used), sort(arguments)))) stop("Must use each number once.")
}</lang> Example Session <lang r>> twenty.four()
Make 24 out of the numbers 1, 6, 7, 5 and the operators +, -, *, /, ( . Enter 'q' to quit, '!' to select new digits, or '?' to repeat this message. > 6*(5-1) Must use each number once. > 1 + 6*5 - 7 Correct! New digits: 7, 2, 9, 3 > (7+9)/2*3 Correct! New digits: 1, 4, 1, 7 > 4*(7-1) Must use each number once. > (7-1)*4*1 Correct! New digits: 1, 5, 2, 8 > (5-1)^2+8 '^' not allowed. > ! New digits: 2, 8, 5, 2 > 52-28 '52, 28' not allowed. > (8-2)*(5-2/2) Must use each number once. > (8+2)*2+5 Evaluated to 25 ( goal 24 ) > q Goodbye! </lang>
Racket
The functional interpreter of an expression given in the infix form. It parses the S-expression representing the user's answer and handles invalid cases.
<lang racket>
- lang racket
(define (interprete expr numbers)
;; the cashe for used numbers (define cashe numbers)
;; updating the cashe and handling invalid cases (define (update-cashe! x) (unless (member x numbers) (error "Number is not in the given set:" x)) (unless (member x cashe) (error "Number is used more times then it was given:" x)) (set! cashe (remq x cashe)))
;; the parser (define parse (match-lambda ;; parsing arythmetics [`(,x ... + ,y ...) (+ (parse x) (parse y))] [`(,x ... - ,y ...) (- (parse x) (parse y))] [`(,x ... * ,y ...) (* (parse x) (parse y))] [`(,x ... / ,y ...) (/ (parse x) (parse y))] [`(,x ,op ,y ...) (error "Unknown operator: " op)] ;; opening redundant brackets [`(,expr) (parse expr)] ;; parsing numbers [(? number? x) (update-cashe! x) x] ;; unknown token [x (error "Not a number: " x)]))
;; parse the expresion (define result (parse expr))
;; return the result if cashe is empty (if (empty? cashe) result (error "You didn`t use all numbers!")))
</lang>
Testing the interpreter:
> (interprete '(1 - 2 * 3 + 8) '(1 2 3 8)) 3 > (interprete '(1 - 2 * (3 + 8)) '(1 2 3 8)) -21 > (interprete '((1 - 2) * (3 + 8)) '(1 2 3 8)) -11 > (interprete '((1 - 2) * 3 + 8) '(1 2 3 8)) 5 > (interprete '((1 - 2) * 3 + 8) '(1 2 3 4)) Number is not in the given set: 8 > (interprete '((1 - 2) * 3 + 2) '(1 2 3 3)) Number is used more times then it was given: 2 > (interprete '((1 - 2) ^ 3 + 2) '(1 2 3 2)) Unknown operator: ^ > (interprete '((1 - 2) * 3) '(1 2 3 2)) You didn`t use all numbers!
The program which uses the interpreter to play the game:
<lang racket>
- starting the program
(define (start)
(displayln "Combine given four numbers using operations + - * / to get 24.") (displayln "Input 'q' to quit or your answer like '1 - 3 * (2 + 3)'") (new-game))
- starting a new game
(define (new-game)
;; create a new number set (define numbers (build-list 4 (λ (_) (+ 1 (random 9))))) (apply printf "Your numbers: ~a ~a ~a ~a\n" numbers) (new-input numbers))
- processing a new user input
(define (new-input numbers)
;; if an exception is raized while processing, show the exeption message ;; and prompt for another input, but do not stop the program. (with-handlers ([exn? (λ (exn) (displayln (exn-message exn)) (new-input numbers))]) ;; get the answer (define user-expr (read-the-answer)) ;; interprete it (case user-expr [(q) (display "Good buy!")] [(n) (new-game)] [else (define ans (interprete user-expr numbers)) (case ans [(24) (printf "Indeed! ~a = 24\n" user-expr) (new-game)] [else (error "Wrong!" user-expr '= ans)])])))
- reading and preparing the user's answer
- "1 + 2 * (3 + 4)" --> '(1 + 2 * (3 + 4))
(define (read-the-answer)
(read (open-input-string (format "(~a)" (read-line)))))
</lang>
Raku
(formerly Perl 6)
<lang perl6>use MONKEY-SEE-NO-EVAL;
say "Here are your digits: ", constant @digits = (1..9).roll(4)».Str;
grammar Exp24 {
token TOP { ^ <exp> $ { fail unless EVAL($/) == 24 } } rule exp { <term>+ % <op> } rule term { '(' <exp> ')' | <@digits> } token op { < + - * / > }
}
while my $exp = prompt "\n24? " {
if try Exp24.parse: $exp { say "You win :)"; last; } else { say ( 'Sorry. Try again.' xx 20, 'Try harder.' xx 5, 'Nope. Not even close.' xx 2, 'Are you five or something?', 'Come on, you can do better than that.' ).flat.pick }
} </lang>
The MONKEY-SEE-NO-EVAL
pragma enables the dangerous EVAL
function, which will compile and execute even user input. In this example, the grammar used to parse the input should ensure that only safe expressions are evaluated.
Red
<lang Red> Red [] print "Evaluation from left to right with no precedence, unless you use parenthesis." print "" a: "123456789" guess: "" valid: "" sucess: false random/seed now/time loop 4 [append valid last random a] print ["The numbers are: " valid/1 ", " valid/2 ", " valid/3 " and " valid/4] sort valid insert valid " "
expr: [term ["+" | "-"] expr | term] term: [primary ["*" | "/"] term | primary] primary: [some digit | "(" expr ")"] digit: charset valid
while [not sucess] [ guess: ask "Enter your expression: " if guess = "q" [halt] numbers: copy guess sort numbers numbers: take/last/part numbers 4 insert numbers " " either (parse guess expr) and (valid = numbers) [ repeat i length? guess [insert at guess (i * 2) " "] result: do guess print ["The result of your expression is: " result] if (result = 24) [sucess: true] ][ print "Something is wrong with the expression, try again." ] ] print "You got it right!"
</lang> Output:
Evaluation from left to right with no precedence, unless you use parenthesis. The numbers are: 7 , 1 , 9 and 3 Enter your expression: 7+1+9 Something is wrong with the expression, try again. Enter your expression: 7+1+8+3 Something is wrong with the expression, try again. Enter your expression: 1+7*(9/3) The result of your expression is: 24 You got it right! >>
REXX
A large part of this program deals with validating the user input (and issuing appropriate and meaningful error
messages), and also that the digits presented to the user, do in fact, have a possible solution.
This REXX version uses an in─line documentation (for help).
<lang rexx>/*REXX program helps the user find solutions to the game of 24.
╔═════════════════════════════════════════════════════════════════════════════╗ ║ Argument is either of these forms: (blank) ║⌂ ║ ssss ║⌂ ║ ssss,total,limit ║⌂ ║ ssss-ffff ║⌂ ║ ssss-ffff,total,limit ║⌂ ║ -ssss ║⌂ ║ +ssss ║⌂ ║ ║⌂ ║ where SSSS and/or FFFF must be exactly four numerals (decimal digits) ║⌂ ║ comprised soley of the numerals (digits) 1 ──► 9 (no zeroes). ║⌂ ║ ║⌂ ║ SSSS is the start, and FFFF is the end (inclusive). ║⌂ ║ ║⌂ ║ If ssss has a leading plus (+) sign, it's used as the digits, and ║⌂ ║ the user is prompted to enter a solution (using those decimal digits). ║⌂ ║ ║⌂ ║ If ssss has a leading minus (-) sign, a solution is searched for and ║⌂ ║ the user is told there is a solution (or not), but no solutions are shown).║⌂ ║ ║⌂ ║ If no argument is specified, this program generates four digits (no zeros) ║⌂ ║ which has at least one solution, and shows the sorted digits to the user, ║⌂ ║ requesting that they enter a solution (the digits used may be in any order).║⌂ ║ ║⌂ ║ If TOTAL is entered, it's the desired answer. The default is 24. ║⌂ ║ If LIMIT is entered, it limits the number of solutions shown. ║⌂ ║ ║⌂ ║ A solution to be entered can be in the form of: ║ ║ ║ ║ digit1 operator digit2 operator digit3 operator digit4 ║ ║ ║ ║ where DIGITn is one of the digits shown (in any order), and ║ ║ OPERATOR can be any one of: + - * / ║ ║ ║ ║ Parentheses () may be used in the normal manner for grouping, as well as ║ ║ brackets [] or braces {}. Blanks can be used anywhere. ║ ║ ║ ║ I.E.: for the digits 3448 the following could be entered: 3*8 + (4-4) ║ ╚═════════════════════════════════════════════════════════════════════════════╝ */
numeric digits 30 /*where rational arithmetic is needed. */ parse arg orig; uargs= orig /*get the guess from the command line*/ orig= space(orig, 0) /*remove all the blanks from ORIG. */ negatory= left(orig, 1)=='-' /*=1, suppresses showing. */ pository= left(orig, 1)=='+' /*=1, force pgm to use specific number.*/ if pository | negatory then orig=substr(orig,2) /*now, just use the absolute vaue. */ parse var orig orig ',' $ "," limit /*get optional total ($) and/or limit*/ parse var orig start '-' finish /*get start and finish (maybe). */ opers= '*' || "/+-" /*arithmetic opers; order is important.*/ ops= length(opers) /*the number of arithmetic operators. */ groupsym= space(' ( ) [ ] { } « » ', 0) /*the allowable grouping symbols. */ indent= left(, 30) /*indents the display of solutions. */ show= 1 /*=1, shows solutions (a semifore). */ digs= 123456789 /*numerals (digits) that can be used.*/ if $== then $= 24 /*the name (goal) of the game: (24) */ if limit== then limit= 1 /*=1, shows only one solution. */ __= copies('─', 8) /*used for output messages to the user.*/ abuttals = 0 /*=1, allows digit abuttal: 12+12 */
do j=1 for ops; o.j= substr(opers, j, 1) /*these are used for fast execution. */ end /*j*/
if \datatype(limit, 'N') then do; call ger limit "isn't numeric"; exit 13; end limit= limit / 1 /*normalize the number for limit. */ if \datatype($, 'N') then do; call ger $ "isn't numeric"; exit 13; end $= $ / 1 /*normalize the number for total. */ if start\== & \pository then do; call ranger start,finish; exit 1; end show= 0 /*stop blabbing solutions in SOLVE. */
do forever while \negatory /*keep truckin' until a solution. */ x.= 0 /*way to hold unique expressions. */ rrrr= random(1111, 9999) /*get a random set of digits. */ if pos(0, rrrr)\==0 then iterate /*but don't the use of zeroes. */ if solve(rrrr)\==0 then leave /*try to solve for these digits. */ end /*forever*/
show= 1 /*enable SOLVE to show solutions. */ if pository then rrrr= start /*use what's specified. */ rrrr= sortc(rrrr) /*sort four elements. */ rd.= x.
do j=1 for 9; _= substr(rrrr, j, 1); rd._= #chrs(rrrr, _) end /*j*/ /* [↑] count for each digit in RRRR. */ do guesses=1; say say __ "Using the numerals (digits) " rrrr", enter an expression that equals " $ say right('(or ? or Quit):', 79) pull y; uargs= y; y= space(y, 0) /*obtain user's response (expression). */ if abbrev('QUIT', y, 1) then exit 0 /*does the user want to quit this game?*/ if y=='?' then do j=2 for sourceline()-1; _= sourceline(j) /*get a line of pgm. */ if right(_, 1)=='⌂' then iterate /*ignore this doc part*/ say ' ' strip( left(_, 79), 'T') /*show " " " doc. */ if left(_, 1)=='╚' then iterate guesses end /*j*/ /* [↑] use an in─line way to show help*/ _v= verify(y, digs || opers || groupsym) /*any illegal characters? */ if _v\==0 then do; call ger 'invalid character:' substr(y, _v, 1); iterate; end if y= then do; call validate y; iterate; end
do j=1 for length(y)-1 while \abuttals /*check for two adjacent decimal digits*/ if datatype( substr(y, j, 1), 'W') & datatype( substr(y, j+1, 1), 'W') then , do; call ger 'invalid use of digit abuttal:' substr(y, j, 2) iterate guesses end end /*j*/
yy= translate(y, ')))', "]}»") /*use a simlier form for the expression*/
do j=1 for 9 while \abuttals /*check for a dig following a group sym*/ _= pos(')'j, yy) /*is there a string with: )DIGIT ? */ if _>0 then do; call ger 'invalid use of digit abuttal' substr(y, _, 2) iterate guesses end end /*j*/
yd= #chrs(y, digs) /*count of legal digits 123456789 */ if yd<4 then do; call ger 'not enough numerals were entered.'; iterate guesses; end if yd>4 then do; call ger 'too many numerals were entered.' ; iterate guesses; end
do j=1 for length(groupsym) by 2 if #chrs(y, substr(groupsym, j , 1))\==, #chrs(y, substr(groupsym, j+1, 1)) then do; call ger 'mismatched' , substr(groupsym, j, 2) iterate guesses end end /*j*/
do k=1 for 2 /*check for ** and // */ _= copies( substr( opers, k, 1), 2) /*only examine the first two operators.*/ if pos(_, y)\==0 then do; call ger 'illegal operator:' _; iterate guesses; end end /*k*/
do j=1 for 9; if rd.j==0 then iterate; _d= #chrs(y, j) if _d==rd.j then iterate if _d<rd.j then call ger 'not enough' j "numerals were entered, must be" rd.j else call ger 'too many' j "numerals were entered, must be" rd.j iterate guesses end /*j*/
y= translate(y, '()()', "[]{}") /*change extended grouping symbols──►()*/ interpret 'ans=(' y ") / 1" /*evalualte a normalized expression. */ oldDigs= digits() /*save current decimal digit setting. */ numeric digits digits()%2 /*normalize expresssion to less digits.*/ if ans/1=$ then leave guesses /*the expression calculates to 24. */ say __ "incorrect, " y"="ans /*issue an error message (incorrect). */ numeric digits oldDigs /*re─instate the decimal digs precision*/ end /*guesses*/
say; say center('┌─────────────────────┐', 79)
say center('│ │', 79) say center('│ congratulations ! │', 79) say center('│ │', 79) say center('└─────────────────────┘', 79); say
exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/
- chrs:procedure; parse arg x,c; return length(x) - length( space( translate(x, , c), 0) )
div: procedure; parse arg q; if q=0 then q=1e9; return q /*tests if dividing by zero.*/ ger: say __ '***error*** for argument: ' uargs; say __ arg(1); errCode= 1; return 0 s: if arg(1)==1 then return arg(3); return word( arg(2) 's', 1) /*──────────────────────────────────────────────────────────────────────────────────────*/ ranger: parse arg ssss,ffff /*parse args passed to this sub. */
ffff= word(ffff ssss, 1) /*create a FFFF if necessary. */ do g=ssss to ffff /*process possible range of values. */ if pos(0, g)\==0 then iterate /*ignore any G number with zeroes. */ sols= solve(g); wols= sols if sols==0 then wols= 'No' /*un─geek number of solutions (if any).*/ if negatory & sols\==0 then wols= 'A' /*found only the first solution? */ if sols==1 & limit==1 then wols= 'A' say; say wols 'solution's(sols) "found for" g if $\==24 then say 'for answers that equal' $ end /*g*/ return
/*──────────────────────────────────────────────────────────────────────────────────────*/ solve: parse arg qqqq; finds= 0; x.=0; nq.= x. /*parse args passed to this function. */
if \validate(qqqq) then return -1 parse value '( (( )) )' with L LL RR R /*assign some static variables (fastly)*/
do jq=1 for 4; _= substr(qqqq,jq,1) /*count the number of each digit. */ nq._= nq._ + 1 end /*jq*/
gLO= 1111; gHI= 9999
if $==24 then do; gLO= 1118; gHI= 9993; end /*24: lowest poss.# that has solutions*/
do gggg=gLO to gHI; if pos(0, gggg)\==0 then iterate /*ignore values with zeroes.*/ if verify(gggg, qqqq)\==0 then iterate if verify(qqqq, gggg)\==0 then iterate ng.= 0 do jg=1 for 4; _= substr(gggg, jg, 1); g.jg= _; ng._= ng._ + 1 end /*jg*/ /* [↑] count the number of each digit.*/ do kg=1 for 9; if nq.kg\==ng.kg then iterate gggg end /*kg*/ /* [↑] verify number has same # digits*/ do i=1 for ops /*insert operator after 1st numeral. */ do j=1 for ops /* " " " 2nd " */ do k=1 for ops /* " " " 3rd " */ do m=0 for 10; !.= /*nullify all grouping symbols (parens)*/ select /*used to generate grouped expressions.*/ when m==1 then do; !.1=L; !.3=R; end when m==2 then do; !.1=L; !.5=R; end when m==3 then do; !.1=L; !.3=R; !.4=L; !.6=R; end when m==4 then do; !.2=L; !.5=R; end when m==5 then do; !.2=L; !.6=R; end when m==6 then do; !.1=LL; !.5=R; !.6=R; end when m==7 then do; !.2=LL; !.5=R; !.6=R; end when m==8 then do; !.1=L; !.2=L; !.6=RR; end when m==9 then do; !.2=L; !.4=L; !.6=RR; end otherwise nop end /*select*/
e= space(!.1 g.1 o.i !.2 g.2 !.3 o.j !.4 g.3 !.5 o.k g.4 !.6, 0) if x.e then iterate /*was the expression already used? */ x.e= 1 /*mark this expression as being used. */ origE= e /*keep original version for the display*/ pd= pos('/(', e) /*find pos of /( in E. */ if pd\==0 then do /*Found? Might have possible ÷ by zero*/ eo= e lr= lastpos(')', e) /*find the last right parenthesis. */ lm= pos('-', e, pd+1) /*find a minus sign (-) after ( */ if lm>pd & lm<lr then e= changestr('/(',e,"/div(") /*change*/ if eo\==e then if x.e then iterate /*expression already used?*/ x.e= 1 /*mark this expression as being used. */ end interpret 'x=(' e ") / 1" /*have REXX do the heavy lifting here. */ if x\==$ then do /*Not correct? Then try again. */ numeric digits 9; x= x / 1 /*re─do evaluation.*/ numeric digits 12 /*re─instate digits*/ if x\==$ then iterate /*Not correct? Then try again. */ end finds= finds + 1 /*bump number of found solutions. */ if \show | negatory then return finds _= translate(origE, '][', ")(") /*display [], not (). */ if show then say indent 'a solution for' gggg':' $"=" _ /*show solution.*/ if limit==1 & finds==limit then leave gggg /*leave big loop*/ end /*m*/ end /*k*/ end /*j*/ end /*i*/ end /*gggg*/
return finds /*──────────────────────────────────────────────────────────────────────────────────────*/ sortc: procedure; arg nnnn; @.= /*sorts the digits of NNNN */
do i=1 for length(nnnn); _= substr(nnnn, i, 1); @._= @._||_; end /*i*/ return @.0 || @.1 || @.2 || @.3 || @.4 || @.5 || @.6 || @.7 || @.8 || @.9
/*──────────────────────────────────────────────────────────────────────────────────────*/ validate: parse arg y; errCode= 0; _v= verify(y, digs)
select when y== then call ger 'no digits were entered.' when length(y)<4 then call ger 'not enough digits entered, must be 4' when length(y)>4 then call ger 'too many digits entered, must be 4' when pos(0,y)\==0 then call ger "can't use the digit 0 (zero)" when _v\==0 then call ger 'illegal character:' substr(y, _v, 1) otherwise nop end /*select*/</lang>
Some older REXXes don't have a changestr BIF, so one is included here ──► CHANGESTR.REX.
- output of a sample execution:
──────── Using the numerals (digits) 1689, enter an expression that equals 24 (or ? or Quit): 8 * {9-6} / 1 ◄■■■■■■■■■■■■■■ this is the user input. ┌─────────────────────┐ │ │ │ congratulations ! │ │ │ └─────────────────────┘
Ring
<lang ring>
- Project : 24 game
load "stdlib.ring" digits = list(4) check = list(4) for choice = 1 to 4
digits[choice] = random(9)
next
see "enter an equation (using all of, and only, the single digits " + nl for index = 1 to 4
see digits[index] if index != 4 see " " ok
next see ")" see " which evaluates to exactly 24. only multiplication (*), division (/)," + nl see "addition (+) & subtraction (-) operations and parentheses are allowed:" + nl see "24 = " give equation see "equation = " + equation + nl
while true
for char = 1 to len(equation) digit = substr("0123456789", equation[char]) - 1 if digit >= 0 for index = 1 to 4 if digit = digits[index] if not check[index] check[index] = 1 exit ok ok next if index > 4 see "sorry, you used the illegal digit " + digit + nl exit 2 ok ok next for index = 1 to 4 if check[index] = 0 see "sorry, you failed to use the digit " + digits[index] + nl exit 2 ok next for pair = 11 to 99 if substr(equation, string(pair)) see "sorry, you may not use a pair of digits " + pair + nl ok next eval("result = " + equation) if result = 24 see "congratulations, you succeeded in the task!" + nl exit else see "sorry, your equation evaluated to " + result + " rather than 24!" + nl ok
end </lang> Output:
enter an equation (using all of, and only, the single digits 3 1 4 5) which evaluates to exactly 24. only multiplication (*), division (/), addition (+) & subtraction (-) operations and parentheses are allowed: 24 = 4*5+3+1 equation = 4*5+3+1 congratulations, you succeeded in the task! enter an equation (using all of, and only, the single digits 5 7 2 5) which evaluates to exactly 24. only multiplication (*), division (/), addition (+) & subtraction (-) operations and parentheses are allowed: 24 = 98+72 equation = 98+72 sorry, you used the illegal digit 9
Ruby
<lang ruby>class Guess < String
def self.play nums = Array.new(4){rand(1..9)} loop do result = get(nums).evaluate! break if result == 24.0 puts "Try again! That gives #{result}!" end puts "You win!" end def self.get(nums) loop do print "\nEnter a guess using #{nums}: " input = gets.chomp return new(input) if validate(input, nums) end end def self.validate(guess, nums) name, error = { invalid_character: ->(str){ !str.scan(%r{[^\d\s()+*/-]}).empty? }, wrong_number: ->(str){ str.scan(/\d/).map(&:to_i).sort != nums.sort }, multi_digit_number: ->(str){ str.match(/\d\d/) } } .find {|name, validator| validator[guess] } error ? puts("Invalid input of a(n) #{name.to_s.tr('_',' ')}!") : true end def evaluate! as_rat = gsub(/(\d)/, '\1r') # r : Rational suffix eval "(#{as_rat}).to_f" rescue SyntaxError "[syntax error]" end
end
Guess.play</lang>
Rust
The solution below converts the infix notation to RPN and then calculates the result.
I am still new to Rust so i am certain it could be written in a shorter way. So if there is someone better than me please feel free to improve.
<lang rust>use std::io::{self,BufRead}; extern crate rand; use rand::Rng;
fn op_type(x: char) -> i32{
match x { '-' | '+' => return 1, '/' | '*' => return 2, '(' | ')' => return -1, _ => return 0, }
}
fn to_rpn(input: &mut String){
let mut rpn_string : String = String::new(); let mut rpn_stack : String = String::new(); let mut last_token = '#'; for token in input.chars(){ if token.is_digit(10) { rpn_string.push(token); } else if op_type(token) == 0 { continue; } else if op_type(token) > op_type(last_token) || token == '(' { rpn_stack.push(token); last_token=token; } else { while let Some(top) = rpn_stack.pop() { if top=='(' { break; } rpn_string.push(top); } if token != ')'{ rpn_stack.push(token); } } } while let Some(top) = rpn_stack.pop() { rpn_string.push(top); }
println!("you formula results in {}", rpn_string);
*input=rpn_string;
}
fn calculate(input: &String, list : &mut [u32;4]) -> f32{
let mut stack : Vec<f32> = Vec::new(); let mut accumulator : f32 = 0.0;
for token in input.chars(){ if token.is_digit(10) { let test = token.to_digit(10).unwrap() as u32; match list.iter().position(|&x| x == test){ Some(idx) => list[idx]=10 , _ => println!(" invalid digit: {} ",test), } stack.push(accumulator); accumulator = test as f32; }else{ let a = stack.pop().unwrap(); accumulator = match token { '-' => a-accumulator, '+' => a+accumulator, '/' => a/accumulator, '*' => a*accumulator, _ => {accumulator},//NOP }; } } println!("you formula results in {}",accumulator); accumulator
}
fn main() {
let mut rng = rand::thread_rng(); let mut list :[u32;4]=[rng.gen::<u32>()%10,rng.gen::<u32>()%10,rng.gen::<u32>()%10,rng.gen::<u32>()%10];
println!("form 24 with using + - / * {:?}",list); //get user input let mut input = String::new(); io::stdin().read_line(&mut input).unwrap(); //convert to rpn to_rpn(&mut input); let result = calculate(&input, &mut list);
if list.iter().any(|&list| list !=10){ println!("and you used all numbers"); match result { 24.0 => println!("you won"), _ => println!("but your formulla doesn't result in 24"), } }else{ println!("you didn't use all the numbers"); }
}</lang>
Scala
The solution below is much more complex than strictly needed, because it shows off Scala's Parser library, which enables easy construction of parsers from EBNF grammars.
Only problems with solution are shown to the user.
def main(args: Array[String]) { import Parser.TwentyFourParser println(welcome) var parser = new TwentyFourParser(problemsIterator.next) println("Your four digits: "+parser+".") var finished = false var expressionCount = 1 do { val line = Console.readLine("Expression "+expressionCount+": ") line match { case "!" => parser = new TwentyFourParser(problemsIterator.next) println("New digits: "+parser+".") case "q" => finished = true case _ => parser readExpression line match { case Some(24) => println("That's right!"); finished = true case Some(n) => println("Sorry, that's "+n+".") case None => } } expressionCount += 1 } while (!finished) println("Thank you and goodbye!") } val welcome = """|The 24 Game | |Given any four digits in the range 1 to 9, which may have repetitions, |Using just the +, -, *, and / operators; and the possible use of |brackets, (), show how to make an answer of 24. | |An answer of "q" will quit the game. |An answer of "!" will generate a new set of four digits. |Otherwise you are repeatedly asked for an expression until it evaluates to 24 | |Note: you cannot form multiple digit numbers from the supplied digits, |so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed. |""".stripMargin val problemsIterator = ( Iterator continually List.fill(4)(scala.util.Random.nextInt(9) + 1 toDouble) filter hasSolution ) def hasSolution(l: List[Double]) = permute(l) flatMap computeAllOperations exists (_ == 24) def computeAllOperations(l: List[Double]): List[Double] = l match { case Nil => Nil case x :: Nil => l case x :: xs => for { y <- computeAllOperations(xs) z <- if (y == 0) List(x*y, x+y, x-y) else List(x*y, x/y, x+y, x-y) } yield z } def permute(l: List[Double]): List[List[Double]] = l match { case Nil => List(Nil) case x :: xs => for { ys <- permute(xs) position <- 0 to ys.length (left, right) = ys splitAt position } yield left ::: (x :: right) } object Parser { /* Arithmetic expression grammar production rules in EBNF form: * * <expr> --> <term> ( '+' <term> | '-' <term> )* * <term> --> <factor> ( '*' <factor> | '/' <factor> )* * <factor> --> '(' <expr> ')' | <digit> * <digit> --> 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 * * Semantically, <digit> can only be a digit from the list of remaining digits. */ class TwentyFourParser(digits: List[Double]) extends scala.util.parsing.combinator.RegexParsers { require(digits.length == 4 && digits.forall(d => 0 <= d && d <= 9)) override val toString = digits.map(_.toInt).mkString(", ") // Grammar def exprConsumingAllDigits = expr ^? (remainingDigits.allDigitsConsumed, digitsRemainingError) // Guarantees all digits consumed def expr : Parser[Double] = term ~ rep( "+" ~ term | "-" ~ term) ^^ solveOperationChain def term = factor ~ rep( "*" ~ factor | "/" ~ factor) ^^ solveOperationChain def factor = "(" ~> expr <~ ")" | digit def digit = digitRegex ^? (remainingDigits.consumeDigit, digitNotAllowedError) def digitRegex = "\\d".r | digitExpected def digitExpected: Parser[String] = ".".r <~ failure(expectedDigitError) // Produces clear error messages // Evaluate expressions def readExpression(input: String): Option[Double] = { remainingDigits = new DigitList(digits) // Initialize list of digits to be consumed parseAll(exprConsumingAllDigits, input) match { case Success(result, _) => Some(result) case NoSuccess(msg, next) => println(ParsingErrorFormatter(msg, next)) None } } // List of digits to be consumed private var remainingDigits: DigitList = _ // Solve partial results from parsing private def solveOperationChain(partialResult: ~[Double,List[~[String,Double]]]): Double = partialResult match { case first ~ chain => chain.foldLeft(first)(doOperation) } private def doOperation(acc: Double, op: ~[String, Double]): Double = op match { case "+" ~ operand => acc + operand case "-" ~ operand => acc - operand case "*" ~ operand => acc * operand case "/" ~ operand => acc / operand case x => error("Unknown operation "+x+".") } // Error messages private def digitNotAllowedError(d: String) = "Digit "+d+" is not allowed here. Available digits: "+remainingDigits+"." private def digitsRemainingError(x: Any) = "Not all digits were consumed. Digits remaining: "+remainingDigits+"." private def expectedDigitError = "Unexpected input. Expected a digit from the list: "+remainingDigits+"." } private object ParsingErrorFormatter { def apply[T](msg: String, next: scala.util.parsing.input.Reader[T]) = "%s\n%s\n%s\n" format (msg, next.source.toString.trim, " "*(next.offset - 1)+"^") } private class DigitList(digits: List[Double]) { private var remainingDigits = digits override def toString = remainingDigits.map(_.toInt).mkString(", ") def consumeDigit: PartialFunction[String, Double] = { case d if remainingDigits contains d.toDouble => val n = d.toDouble remainingDigits = remainingDigits diff List(n) n } def allDigitsConsumed: PartialFunction[Double, Double] = { case n if remainingDigits.isEmpty => n } } }}</lang>
- Output:
C:\Workset>scala TwentyFourGame The 24 Game Given any four digits in the range 1 to 9, which may have repetitions, Using just the +, -, *, and / operators; and the possible use of brackets, (), show how to make an answer of 24. An answer of "q" will quit the game. An answer of "!" will generate a new set of four digits. Otherwise you are repeatedly asked for an expression until it evaluates to 24 Note: you cannot form multiple digit numbers from the supplied digits, so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed. Your four digits: 2, 7, 7, 2. Expression 1: 2*7+2+7 Sorry, that's 23.0. Expression 2: 7*7/2-2 Sorry, that's 22.5. Expression 3: 2*7+(7-2) Sorry, that's 19.0. Expression 4: 2*(7+7-2) That's right! Thank you and goodbye!
Scheme
This uses read to read in a scheme expression, and eval to evaluate it, so in that sense it's not ideal (eval is evil etc.) but any expression that is valid should be safe and terminate in a timely manner.
<lang scheme>#lang scheme (require srfi/27 srfi/1) ;; random-integer, every
(define (play)
(let* ([numbers (build-list 4 (lambda (n) (add1 (random-integer 9))))] [valid? (curryr valid? numbers)]) (printf startup-message numbers) (let loop ([exp (read)]) (with-handlers ([exn:fail? (lambda (err) (printf error-message exp (exn-message err)) (loop (read)))]) (cond [(eq? exp '!) (play)] [(or (eq? exp 'q) (eof-object? exp)) (printf quit-message)] [(not (valid? exp)) (printf bad-exp-message exp) (loop (read))] [(not (= (eval exp) 24)) (printf bad-result-message exp (eval exp)) (loop (read))] [else (printf winning-message)])))))
(define (valid? exp numbers)
;; must contain each number exactly once and only valid symbols (define (valid-symbol? sym) ;; only +, -, *, and / are valid (case sym [(+ - * /) #t] [else #f])) (let* ([ls (flatten exp)] [numbers* (filter number? ls)] [symbols (remove number? ls)]) (and (equal? (sort numbers <) (sort numbers* <)) (every valid-symbol? symbols))))
(define startup-message " Write a lisp expression that evaluates to 24 using only (, ), +, -, *, / and these four numbers: ~a
or '!' to get a new set of numbers or 'q' to quit")
(define error-message " Your expression ~a raised an exception:
\"~a\"
Please try again")
(define bad-exp-message "Sorry, ~a is a bad expression.") (define bad-result-message "Sorry, ~a evaluates to ~a, not 24.") (define quit-message "Thanks for playing...") (define winning-message "You win!")
(provide play) </lang>
- Output:
> (require "24game.ss") > (play) Write a lisp expression that evaluates to 24 using only (, ), +, -, *, / and these four numbers: (2 7 2 5) or '!' to get a new set of numbers or 'q' to quit ! Write a lisp expression that evaluates to 24 using only (, ), +, -, *, / and these four numbers: (9 2 7 6) or '!' to get a new set of numbers or 'q' to quit (9 7 6 2) Your expression (9 7 6 2) raised an exception: "procedure application: expected procedure, given: 9; arguments were: 7 6 2" Please try again (+ 9 7 6 2) You win!
Sidef
<lang ruby>const digits = (1..9 -> pick(4)) const grammar = Regex(
'^ (?&exp) \z (?(DEFINE) (?<exp> ( (?&term) (?&op) (?&term) )+ ) (?<term> \( (?&exp) \) | [' + digits.join + ']) (?<op> [\-+*/] ) )', 'x'
)
say "Here are your digits: #{digits.join(' ')}"
loop {
var input = read("Expression: ", String)
var expr = input expr -= /\s+/g # remove all whitespace
if (input == 'q') { say "Goodbye. Sorry you couldn't win." break }
var given_digits = digits.map{.to_s}.sort.join var entry_digits = input.scan(/\d/).sort.join
if ((given_digits != entry_digits) || (expr !~ grammar)) { say "That's not valid" next }
given(var n = eval(input)) { when (24) { say "You win!"; break } default { say "Sorry, your expression is #{n}, not 24" } }
}</lang>
- Output:
Here are your digits: 8 2 3 4 Expression: 8 * (2 - (3 + 4)) Sorry, your expression is -40, not 24 Expression: 8 * (2 - (3 - That's not valid Expression: 8 * (2 - (3 - 4)) You win!
Simula
<lang simula>BEGIN
CLASS EXPR; BEGIN
REAL PROCEDURE POP; BEGIN IF STACKPOS > 0 THEN BEGIN STACKPOS := STACKPOS - 1; POP := STACK(STACKPOS); END; END POP;
PROCEDURE PUSH(NEWTOP); REAL NEWTOP; BEGIN STACK(STACKPOS) := NEWTOP; STACKPOS := STACKPOS + 1; END PUSH;
REAL PROCEDURE CALC(OPERATOR, ERR); CHARACTER OPERATOR; LABEL ERR; BEGIN REAL X, Y; X := POP; Y := POP; IF OPERATOR = '+' THEN PUSH(Y + X) ELSE IF OPERATOR = '-' THEN PUSH(Y - X) ELSE IF OPERATOR = '*' THEN PUSH(Y * X) ELSE IF OPERATOR = '/' THEN BEGIN IF X = 0 THEN BEGIN EVALUATEDERR :- "DIV BY ZERO"; GOTO ERR; END; PUSH(Y / X); END ELSE BEGIN EVALUATEDERR :- "UNKNOWN OPERATOR"; GOTO ERR; END END CALC;
PROCEDURE READCHAR(CH); NAME CH; CHARACTER CH; BEGIN IF T.MORE THEN CH := T.GETCHAR ELSE CH := EOT; END READCHAR;
PROCEDURE SKIPWHITESPACE(CH); NAME CH; CHARACTER CH; BEGIN WHILE (CH = SPACE) OR (CH = TAB) OR (CH = CR) OR (CH = LF) DO READCHAR(CH); END SKIPWHITESPACE;
PROCEDURE BUSYBOX(OP, ERR); INTEGER OP; LABEL ERR; BEGIN CHARACTER OPERATOR; REAL NUMBR; BOOLEAN NEGATIVE;
SKIPWHITESPACE(CH);
IF OP = EXPRESSION THEN BEGIN
NEGATIVE := FALSE; WHILE (CH = '+') OR (CH = '-') DO BEGIN IF CH = '-' THEN NEGATIVE := NOT NEGATIVE; READCHAR(CH); END;
BUSYBOX(TERM, ERR);
IF NEGATIVE THEN BEGIN NUMBR := POP; PUSH(0 - NUMBR); END;
WHILE (CH = '+') OR (CH = '-') DO BEGIN OPERATOR := CH; READCHAR(CH); BUSYBOX(TERM, ERR); CALC(OPERATOR, ERR); END;
END ELSE IF OP = TERM THEN BEGIN
BUSYBOX(FACTOR, ERR); WHILE (CH = '*') OR (CH = '/') DO BEGIN OPERATOR := CH; READCHAR(CH); BUSYBOX(FACTOR, ERR); CALC(OPERATOR, ERR) END
END ELSE IF OP = FACTOR THEN BEGIN
IF (CH = '+') OR (CH = '-') THEN BUSYBOX(EXPRESSION, ERR) ELSE IF (CH >= '0') AND (CH <= '9') THEN BUSYBOX(NUMBER, ERR) ELSE IF CH = '(' THEN BEGIN READCHAR(CH); BUSYBOX(EXPRESSION, ERR); IF CH = ')' THEN READCHAR(CH) ELSE GOTO ERR; END ELSE GOTO ERR;
END ELSE IF OP = NUMBER THEN BEGIN
NUMBR := 0; WHILE (CH >= '0') AND (CH <= '9') DO BEGIN NUMBR := 10 * NUMBR + RANK(CH) - RANK('0'); READCHAR(CH); END; IF CH = '.' THEN BEGIN REAL FAKTOR; READCHAR(CH); FAKTOR := 10; WHILE (CH >= '0') AND (CH <= '9') DO BEGIN NUMBR := NUMBR + (RANK(CH) - RANK('0')) / FAKTOR; FAKTOR := 10 * FAKTOR; READCHAR(CH); END; END; PUSH(NUMBR);
END;
SKIPWHITESPACE(CH);
END BUSYBOX;
BOOLEAN PROCEDURE EVAL(INP); TEXT INP; BEGIN EVALUATEDERR :- NOTEXT; STACKPOS := 0; T :- COPY(INP.STRIP); READCHAR(CH); BUSYBOX(EXPRESSION, ERRORLABEL); ! OUTTEXT("T = '"); ! OUTTEXT(T); ! OUTTEXT("'"); ! OUTTEXT(", T.POS = "); ! OUTINT(T.POS, 0); ! OUTTEXT(", STACKPOS = "); ! OUTINT(STACKPOS, 0); ! OUTTEXT(", T.MORE = "); ! OUTCHAR(IF T.MORE THEN 'T' ELSE 'F'); ! OUTTEXT(", CH = "); ! OUTCHAR(CH); ! OUTIMAGE; IF NOT T.MORE AND STACKPOS = 1 AND CH = EOT THEN BEGIN EVALUATED := POP; EVAL := TRUE; GOTO NOERRORLABEL; END; ERRORLABEL: EVAL := FALSE; IF EVALUATEDERR = NOTEXT THEN EVALUATEDERR :- "INVALID EXPRESSION: " & INP; NOERRORLABEL: END EVAL;
REAL PROCEDURE RESULT; RESULT := EVALUATED;
TEXT PROCEDURE ERR; ERR :- EVALUATEDERR;
TEXT T;
INTEGER EXPRESSION; INTEGER TERM; INTEGER FACTOR; INTEGER NUMBER;
CHARACTER TAB; CHARACTER LF; CHARACTER CR; CHARACTER SPACE; CHARACTER EOT;
CHARACTER CH; REAL ARRAY STACK(0:31); INTEGER STACKPOS;
REAL EVALUATED; TEXT EVALUATEDERR;
EXPRESSION := 1; TERM := 2; FACTOR := 3; NUMBER := 4;
TAB := CHAR(9); LF := CHAR(10); CR := CHAR(13); SPACE := CHAR(32); EOT := CHAR(0);
END EXPR;
INTEGER ARRAY DIGITS(1:4); INTEGER SEED, I; REF(EXPR) E;
E :- NEW EXPR; OUTTEXT("ENTER RANDOM SEED: "); OUTIMAGE; SEED := ININT; FOR I := 1 STEP 1 UNTIL 4 DO DIGITS(I) := RANDINT(0, 9, SEED);
L: BEGIN
INTEGER ARRAY DIGITSUSED(0:9); INTEGER ARRAY DIGITSTAKEN(0:9); CHARACTER C, LASTC; TEXT INP;
LASTC := CHAR(0); OUTTEXT("MAKE 24 USING THESE DIGITS: "); FOR I := 1 STEP 1 UNTIL 4 DO BEGIN OUTINT(DIGITS(I), 2); DIGITSUSED( DIGITS(I) ) := DIGITSUSED( DIGITS(I) ) + 1; END; OUTIMAGE; INIMAGE; INP :- COPY(SYSIN.IMAGE.STRIP); OUTIMAGE; WHILE INP.MORE DO BEGIN C := INP.GETCHAR; IF (C >= '0') AND (C <= '9') THEN BEGIN INTEGER D; IF (LASTC >= '0') AND (LASTC <= '9') THEN BEGIN OUTTEXT("NUMBER HAS TOO MANY DIGITS: "); OUTCHAR(LASTC); OUTCHAR(C); OUTIMAGE; GOTO L; END; D := RANK(C) - RANK('0'); DIGITSTAKEN(D) := DIGITSTAKEN(D) + 1; END ELSE IF NOT ((C = '+') OR (C = '-') OR (C = '/') OR (C = '*') OR (C = ' ') OR (C = '(') OR (C = ')')) THEN BEGIN OUTTEXT("ILLEGAL INPUT CHARACTER: "); OUTCHAR(C); OUTIMAGE; GOTO L; END; LASTC := C; END; FOR I := 0 STEP 1 UNTIL 9 DO BEGIN IF DIGITSUSED(I) <> DIGITSTAKEN(I) THEN BEGIN OUTTEXT("NOT THE SAME DIGITS."); OUTIMAGE; GOTO L; END; END; IF E.EVAL(INP) THEN BEGIN OUTTEXT("RESULT IS "); OUTFIX(E.RESULT, 4, 10); OUTIMAGE; OUTTEXT(IF ABS(E.RESULT - 24) < 0.001 THEN "YOU WIN" ELSE "YOU LOOSE"); OUTIMAGE; END ELSE BEGIN OUTTEXT(E.ERR); OUTIMAGE; END; END;
END. </lang>
- Output:
ENTER RANDOM SEED:
- Input:
787
- Output:
MAKE 24 USING THESE DIGITS: 6 7 3 9
- Input:
(9 - 7 + 6) * 3
- Output:
RESULT IS 24.0000 YOU WIN
Swift
<lang swift>import Darwin import Foundation
println("24 Game") println("Generating 4 digits...")
func randomDigits() -> Int[] {
var result = Int[](); for var i = 0; i < 4; i++ { result.append(Int(arc4random_uniform(9)+1)) } return result;
}
// Choose 4 digits let digits = randomDigits()
print("Make 24 using these digits : ")
for digit in digits {
print("\(digit) ")
} println()
// get input from operator var input = NSString(data:NSFileHandle.fileHandleWithStandardInput().availableData, encoding:NSUTF8StringEncoding)
var enteredDigits = Int[]()
var enteredOperations = Character[]()
let inputString = input as String
// store input in the appropriate table for character in inputString {
switch character { case "1", "2", "3", "4", "5", "6", "7", "8", "9": let digit = String(character) enteredDigits.append(digit.toInt()!) case "+", "-", "*", "/": enteredOperations.append(character) case "\n": println() default: println("Invalid expression") }
}
// check value of expression provided by the operator var value = Int()
if enteredDigits.count == 4 && enteredOperations.count == 3 {
value = enteredDigits[0] for (i, operation) in enumerate(enteredOperations) { switch operation { case "+": value = value + enteredDigits[i+1] case "-": value = value - enteredDigits[i+1] case "*": value = value * enteredDigits[i+1] case "/": value = value / enteredDigits[i+1] default: println("This message should never happen!") } }
}
if value != 24 {
println("The value of the provided expression is \(value) instead of 24!")
} else {
println("Congratulations, you found a solution!")
} </lang>
Tcl
This version also terminates cleanly on end-of-file. <lang tcl># Four random non-zero digits proc choose4 {} {
set digits {} foreach x {1 2 3 4} {lappend digits [expr {int(1+rand()*9)}]} return [lsort $digits]
}
- Print out a welcome message
proc welcome digits {
puts [string trim "
The 24 Game
Given any four digits in the range 1 to 9, which may have repetitions, Using just the +, -, *, and / operators; and the possible use of brackets, (), show how to make an answer of 24.
An answer of \"q\" will quit the game. An answer of \"!\" will generate a new set of four digits. Otherwise you are repeatedly asked for an expression until it evaluates to 24
Note: you cannot form multiple digit numbers from the supplied digits, so an answer of 12+12 when given 1, 2, 2, and 1 would not be allowed.
"] puts "\nYour four digits: $digits"
}
- Check whether we've got a legal answer
proc check {answer digits} {
if {
[regexp "\[^-+*/() \t[join $digits {}]\]" $answer] || [regexp {\d\d} $answer]
} then {
return false
} set digs [lsort [regexp -inline -all {\d} $answer]] if {$digs ne $digits} {
return false
} expr {![catch {expr $answer}]}
}
- The main game loop
proc main {} {
fconfigure stdout -buffering none
set digits [choose4] welcome $digits set trial 0 while true {
puts -nonewline "Expression [incr trial]: " gets stdin answer
# Check for various types of non-answer
if {[eof stdin] || $answer eq "q" || $answer eq "Q"} { break } elseif {$answer eq "!"} { set digits [choose4] puts "New digits: $digits" continue } elseif {![check $answer $digits]} { puts "The input '$answer' was wonky!"
continue
}
# Check to see if it is the right answer
set ans [expr [regsub {\d} $answer {&.0}]] puts " = [string trimright $ans .0]" if {$ans == 24.0} { puts "That's right!"
break
}
} puts "Thank you and goodbye"
} main</lang>
TorqueScript
Includes an equation parser to avoid using eval. To use, type startTwentyFourGame(); in the console. <lang Torque>function startTwentyFourGame() { if($numbers !$= "") { echo("Ending current 24 game..."); endTwentyFourGame(); }
echo("Welcome to the 24 game!"); echo("Generating 4 numbers..."); for(%a = 0; %a < 4; %a++) $numbers = setWord($numbers, %a, getRandom(0, 9));
echo("Numbers generated! Here are your numbers:"); echo($numbers); echo("Use try24Equation( equation ); to try and guess the equation.");
$TwentyFourGame = 1; }
function endTwentyFourGame() { if(!$TwentyFourGame) { echo("No 24 game is active!"); return false; }
echo("Ending the 24 game."); $numbers = ""; $TwentyFourGame = 0; }
function try24Equation(%equ) { if(!$TwentyFourGame) { echo("No 24 game is active!"); return false; } %numbers = "0123456789"; %operators = "+-*x/()"; %tempchars = $numbers; %other = strReplace(%tempchars, " ", "");
//Check it and make sure it has all the stuff %equ = strReplace(%equ, " ", ""); %length = strLen(%equ);
for(%a = 0; %a < %Length; %a++) { %Char = getSubStr(%equ, %a, 1); if(%a+1 != %Length) %Next = getSubStr(%equ, %a+1, 1); else %Next = " ";
if(strPos(%numbers @ %operators, %char) < 0) { echo("The equation you entered is invalid! Try again."); return false; } if(strPos(%tempchars, %char) < 0 && strPos(%operators, %char) < 0) { echo("The equation you entered uses a number you were not given! Try again."); return false; } else if(strPos(%numbers, %next) >= 0 && strPos(%numbers, %char) >= 0) { echo("No numbers above 9 please! Try again."); echo(%next SPC %char SPC %a); return false; } else if(strPos(%operators, %char) > 0) continue;
%pos = 2*strPos(%other, %char); if(%pos < 0) return "ERROROMG";
//Remove it from the allowed numbers %tempchars = removeWord(%tempchars, %pos/2); %other = getSubStr(%other, 0, %pos) @ getSubStr(%other, %pos+1, strLen(%other));
} %result = doEquation(%equ); if(%result != 24) { echo("Your equation resulted to" SPC %result @ ", not 24! Try again."); return false; } for(%a = 0; %a < 4; %a++) $numbers = setWord($numbers, %a, getRandom(0, 9)); echo("Great job!" SPC %equ SPC "Does result to 24! Here's another set for you:"); echo($numbers);
}
//Evaluates an equation without using eval. function doEquation(%equ) { //Validate the input
%equ = strReplace(%equ, " ", "");%equ = strReplace(%equ, "*", "x"); %equ = strReplace(%equ, "+", " + ");%equ = strReplace(%equ, "x", " x "); %equ = strReplace(%equ, "/", " / ");%equ = strReplace(%equ, "-", " - "); //Parenthesis' while(strPos(%equ, "(") > -1 && strPos(%equ, ")") > 0) { %start = strPos(%equ, "("); %end = %start; %level = 1; while(%level != 0 && %end != strLen(%equ)) { %end++; if(getsubStr(%equ, %end, 1) $= "(") %level++; if(getsubStr(%equ, %end, 1) $= ")") %level--; } if(%level != 0) return "ERROR"; %inbrackets = getsubStr(%equ, %start+1, %end - strLen(getsubStr(%equ, 0, %start + 1))); %leftofbrackets = getsubStr(%equ, 0, %start); %rightofbrackets = getsubStr(%equ, %end + 1, strLen(%equ) - %end); %equ = %leftofbrackets @ doEquation(%inbrackets) @ %rightofbrackets; } if(strPos(%equ, "ERROR") >= 0) return "ERROR"; //Multiplication/Division loop for(%a = 0; %a < getWordCount(%equ); %a++) { if(getWord(%equ, %a) $= "x" || getWord(%equ, %a) $= "/" && %a != 0) { %f = getWord(%equ, %a - 1); %l = getWord(%equ, %a + 1); %o = getWord(%equ, %a); switch$(%o) { case "x": %a--; %equ = removeWord(removeWord(setWord(%equ, %a+1, %f * %l), %a+2), %a); case "/": %a--; %equ = removeWord(removeWord(setWord(%equ, %a+1, %f / %l), %a+2), %a); } } } //Addition/Subraction loop for(%a = 0; %a < getWordCount(%equ); %a++) { if(getWord(%equ, %a) $= "+" || getWord(%equ, %a) $= "-" && %a != 0) { %f = getWord(%equ, %a - 1); %l = getWord(%equ, %a + 1); %o = getWord(%equ, %a); switch$(%o) { case "+": %a--; %equ = removeWord(removeWord(setWord(%equ, %a+1, %f + %l), %a+2), %a); case "-": %a--; %equ = removeWord(removeWord(setWord(%equ, %a+1, %f - %l), %a+2), %a); } } } return %equ;
}</lang>
TUSCRIPT
<lang tuscript> $$ MODE TUSCRIPT BUILD X_TABLE blanks = ":': :"
SECTION game operators="*'/'+'-'(')",numbers=""
LOOP n=1,4 number=RANDOM_NUMBERS (1,9,1) numbers=APPEND(numbers,number) ENDLOOP
SET allowed=APPEND (numbers,operators) SET allowed=MIXED_SORT (allowed) SET allowed=REDUCE (allowed) BUILD S_TABLE ALLOWED =* DATA '{allowed}'
SET checksum=DIGIT_SORT (numbers)
printnumbers=EXCHANGE (numbers,blanks) printoperat=EXCHANGE (operators,blanks)
PRINT "Your numbers ", printnumbers PRINT "Use only these operators ", printoperat PRINT "Enter an expression that equates to 24" PRINT "Enter 'l' for new numbers" PRINT "Your 4 digits: ",printnumbers
DO play ENDSECTION
SECTION check_expr
SET pos = VERIFY (expr,allowed) IF (pos!=0) THEN PRINT "wrong entry on position ",pos DO play STOP ELSE SET yourdigits = STRINGS (expr,":>/:") SET yourchecksum = DIGIT_SORT (yourdigits) IF (checksum!=yourchecksum) THEN PRINT/ERROR "wrong digits" DO play STOP ELSE CONTINUE ENDIF ENDIF
ENDSECTION
SECTION play LOOP n=1,3 ASK "Expression {n}": expr="" IF (expr=="l") THEN RELEASE S_TABLE allowed PRINT "Your new numbers" DO game ELSEIF (expr!="") THEN DO check_expr sum={expr}
IF (sum!=24) THEN PRINT/ERROR expr," not equates 24 but ",sum CYCLE ELSE PRINT "BINGO ", expr," equates ", sum STOP ENDIF
ELSE
CYCLE
ENDIF ENDLOOP ENDSECTION DO game </lang>
- Output:
Your numbers 2 8 9 9 Use only these operators * / + - ( ) Enter an expression that equates to 24 Enter 'l' for new numbers Your 4 digits: 2 8 9 9 Expression 1 >l Your new numbers Your numbers 2 4 2 3 Use only these operators * / + - ( ) Enter an expression that equates to 24 Enter 'l' for new numbers Your 4 digits: 2 4 2 3 Expression 1 >2+4+2+3 @@@@@@@@ 2+4+2+3 not equates 24 but 11 @@@@@@@@ Expression 2 >2+2+2+3 @@@@@@@@ wrong digits @@@@@@@@ Expression 1 >2+2+a+3 wrong entry on position 5 Expression 1 >(2+4+2)*3 BINGO (2+4+2)*3 equates 24
UNIX Shell
Tried to be POSIX. Not sure about corner-cases. <lang bash>gen_digits() {
awk 'BEGIN { srand() for(i = 1; i <= 4; i++) print 1 + int(9 * rand()) }' | sort
}
same_digits() {
[ "$(tr -dc 0-9 | sed 's/./&\n/g' | grep . | sort)" = "$*" ]
}
guessed() {
[ "$(echo "$1" | tr -dc '\n0-9()*/+-' | bc 2>/dev/null)" = 24 ]
}
while :
do
digits=$(gen_digits) echo echo Digits: $digits read -r expr
echo " $expr" | same_digits "$digits" || \ { echo digits should be: $digits; continue; }
guessed "$expr" && message=correct \ || message=wrong
echo $message
done</lang>
VBA
<lang vb> Sub Rosetta_24game()
Dim Digit(4) As Integer, i As Integer, iDigitCount As Integer Dim stUserExpression As String Dim stFailMessage As String, stFailDigits As String Dim bValidExpression As Boolean, bValidDigits As Boolean, bValidChars As Boolean Dim vResult As Variant, vTryAgain As Variant, vSameDigits As Variant
' Generate 4 random digits GenerateNewDigits:
For i = 1 To 4 Digit(i) = [randbetween(1,9)] Next i
' Get user expression GetUserExpression:
bValidExpression = True stFailMessage = "" stFailDigits = "" stUserExpression = InputBox("Enter a mathematical expression which results in 24, using the following digits: " & _ Digit(1) & ", " & Digit(2) & ", " & Digit(3) & " and " & Digit(4), "Rosetta Code | 24 Game")
' Check each digit is included in user expression
bValidDigits = True stFailDigits = "" For i = 1 To 4 If InStr(stUserExpression, Digit(i)) = 0 Then bValidDigits = False stFailDigits = stFailDigits & " " & Digit(i) End If Next i If bValidDigits = False Then bValidExpression = False stFailMessage = "Your expression excluded the following required digits: " & stFailDigits & vbCr & vbCr End If
' Check each character of user expression is a valid character type
bValidDigits = True stFailDigits = "" For i = 1 To Len(stUserExpression) If InStr("0123456789+-*/()", Mid(stUserExpression, i, 1)) = 0 Then bValidDigits = False stFailDigits = stFailDigits & " " & Mid(stUserExpression, i, 1) End If Next i If bValidDigits = False Then bValidExpression = False stFailMessage = stFailMessage & "Your expression contained invalid characters:" & stFailDigits & vbCr & vbCr End If
' Check no disallowed integers entered
bValidDigits = True stFailDigits = "" iDigitCount = 0 For i = 1 To Len(stUserExpression) If Not InStr("0123456789", Mid(stUserExpression, i, 1)) = 0 Then iDigitCount = iDigitCount + 1 If IsError(Application.Match(--(Mid(stUserExpression, i, 1)), Digit, False)) Then bValidDigits = False stFailDigits = stFailDigits & " " & Mid(stUserExpression, i, 1) End If End If Next i If iDigitCount > 4 Then bValidExpression = False stFailMessage = stFailMessage & "Your expression contained more than 4 digits" & vbCr & vbCr End If If iDigitCount < 4 Then bValidExpression = False stFailMessage = stFailMessage & "Your expression contained less than 4 digits" & vbCr & vbCr End If If bValidDigits = False Then bValidExpression = False stFailMessage = stFailMessage & "Your expression contained invalid digits:" & stFailDigits & vbCr & vbCr End If
' Check no double digit numbers entered
bValidDigits = True stFailDigits = "" For i = 11 To 99 If Not InStr(stUserExpression, i) = 0 Then bValidDigits = False stFailDigits = stFailDigits & " " & i End If Next i If bValidDigits = False Then bValidExpression = False stFailMessage = stFailMessage & "Your expression contained invalid numbers:" & stFailDigits & vbCr & vbCr End If
' Check result of user expression
On Error GoTo EvalFail vResult = Evaluate(stUserExpression) If Not vResult = 24 Then bValidExpression = False stFailMessage = stFailMessage & "Your expression did not result in 24. It returned: " & vResult End If
' Return results
If bValidExpression = False Then vTryAgain = MsgBox(stFailMessage & vbCr & vbCr & "Would you like to try again?", vbCritical + vbRetryCancel, "Rosetta Code | 24 Game | FAILED") If vTryAgain = vbRetry Then vSameDigits = MsgBox("Do you want to use the same numbers?", vbQuestion + vbYesNo, "Rosetta Code | 24 Game | RETRY") If vSameDigits = vbYes Then GoTo GetUserExpression Else GoTo GenerateNewDigits End If End If Else vTryAgain = MsgBox("You entered: " & stUserExpression & vbCr & vbCr & "which resulted in: " & vResult, _ vbInformation + vbRetryCancel, "Rosetta Code | 24 Game | SUCCESS") If vTryAgain = vbRetry Then GoTo GenerateNewDigits End If End If Exit Sub
EvalFail:
bValidExpression = False vResult = Err.Description Resume
End Sub
</lang>
Wren
<lang ecmascript>import "random" for Random import "/ioutil" for Input import "/seq" for Stack
var R = Random.new()
class Game24 {
static run() { var digits = List.filled(4, 0) for (i in 0..3) digits[i] = R.int(1, 10) System.print("Make 24 using these digits: %(digits)") var cin = Input.text("> ") var s = Stack.new() var total = 0 for (c in cin) { var d = c.bytes[0] if (d >= 48 && d <= 57) { d = d - 48 total = total + (1 << (d*5)) s.push(d) } else if ("+-*/".indexOf(c) != -1) s.push(applyOperator_(s.pop(), s.pop(), c)) } if (tallyDigits_(digits) != total) { System.write("Not the same digits.") } else if ((24 - s.peek()).abs < 0.001) { System.print("Correct!") } else { System.write("Not correct.") } }
static applyOperator_(a, b, c) { if (c == "+") return a + b if (c == "-") return b - a if (c == "*") return a * b if (c == "/") return b / a return 0/0 }
static tallyDigits_(a) { var total = 0 for (i in 0...a.count) total = total + (1 << (a[i]*5)) return total }
}
Game24.run()</lang>
- Output:
Sample game:
Make 24 using these digits: [2, 3, 5, 1] > 23*51-* Correct!
Yabasic
With reverse polish notation <lang Yabasic>operadores$ = "*/+-" espacios$ = " "
clear screen print "24 Game" print "============\n" print "The player is provided with 4 numbers with which to perform operations" print "of addition (+), subtraction (-), multiplication (*) or division (/) to attempt" print "to get 24 as result." print "Use reverse Polish notation (first the operands and then the operators)." print "For example: instead of 2 + 4, type 2 4 +\n\n"
repeat print at(0,9) espacios$, espacios$, espacios$, espacios$, espacios$, espacios$ print at(0,9); serie$ = ordenaCadena$(genSerie$()) validos$ = serie$+operadores$ line input "Enter your formula in reverse Polish notation: " entrada$ entrada$ = quitaEspacios$(entrada$) entradaOrd$ = ordenaCadena$(entrada$) if (right$(entradaOrd$,4) <> serie$) or (len(entradaOrd$)<>7) then print "Error in the entered series" else resultado = evaluaEntrada(entrada$) print "The result is = ",resultado," " if resultado = 24 then print "Correct!" else print "Error!" end if end if print "Want to try again? (press N to exit, or another key to continue)" until(upper$(left$(inkey$(),1)) = "N")
sub genSerie$() local i, c$, s$
print "The numbers to be used are: "; i = ran() for i = 1 to 4 c$ = str$(int(ran(9))+1) print c$," "; s$ = s$ + c$ next i print return s$ end sub
sub evaluaEntrada(entr$)
local d1, d2, c$, n(4), i
while(entr$<>"") c$ = left$(entr$,1) entr$ = mid$(entr$,2) if instr(serie$,c$) then i = i + 1 n(i) = val(c$) elseif instr(operadores$,c$) then d2 = n(i) n(i) = 0 i = i - 1 d1 = n(i) n(i) = evaluador(d1, d2, c$) else print "Invalid sign" return end if wend
return n(i)
end sub
sub evaluador(d1, d2, op$)
local t
switch op$ case "+": t = d1 + d2 : break case "-": t = d1 - d2 : break case "*": t = d1 * d2 : break case "/": t = d1 / d2 : break end switch
return t end sub
sub quitaEspacios$(entr$)
local n, i, s$, t$(1)
n = token(entr$,t$()," ")
for i=1 to n s$ = s$ + t$(i) next i return s$ end sub
sub ordenaCadena$(cadena$)
local testigo, n, fin, c$
fin = len(cadena$)-1 repeat testigo = false for n = 1 to fin if mid$(cadena$,n,1) > mid$(cadena$,n+1,1) then testigo = true c$ = mid$(cadena$,n,1) mid$(cadena$,n,1) = mid$(cadena$,n+1,1) mid$(cadena$,n+1,1) = c$ end if next n until(testigo = false) return cadena$ end sub</lang>
<lang Yabasic>do clear screen n$="" for i=1 to 4 n$=n$+str$(int(ran(9)+1)) next i print at(35,0) "24 GAME\n" print "Combine numbers and operators for obtain 24." print "Allowed characters: "; i$=n$+"+-*/()" for i=1 to 10 print mid$(i$,i,1)," "; next i print "[nothing to end program]\n" label accept p$="" i$=n$+"+-*/()" print at(0,4);:input "Enter the formula: " f$ if f$="" end for i=1 to len(f$) c$=mid$(f$,i,1) switch c$ case " ": f$=left$(f$,i-1)+right$(f$,len(f$)-i): break case "+":case "-":case "*":case "/": p$=p$+"o": break case "(":case ")": p$=p$+c$: break case mid$(i$,1,1): p$=p$+"n": mid$(i$,1,1)=" ": break case mid$(i$,2,1): p$=p$+"n": mid$(i$,2,1)=" ": break case mid$(i$,3,1): p$=p$+"n": mid$(i$,3,1)=" ": break case mid$(i$,4,1): p$=p$+"n": mid$(i$,4,1)=" ": break default: message(" = Invalid argument! "): break end switch if f$="" goto accept next i restore for i=1 to 11 read t$ if t$=p$ break next i if t$<>p$ then message(" = Bad construction! ") goto accept end if let r=eval(f$) print "\n",f$," = ",r," "; if r<>24 then message(" = Wrong! ") goto accept else message(" = Correct! ") pause 5 end if loop
DATA "nononon" DATA "(non)onon" DATA "nono(non)" DATA "no(no(non))" DATA "((non)on)on" DATA "no(non)on" DATA "(non)o(non)" DATA "no((non)on)" DATA "(nonon)on" DATA "(no(non))on" DATA "no(nonon)"
sub message(m$) print at(0,7) f$,m$ beep: beep: beep pause 1 print at(19,4) " " f$="" end sub
sub eval(c$) static linea
linea=linea+1 c$="sub s"+str$(linea+1000000,"#######")+"():return "+c$+":end sub" compile c$ return execute(mid$(c$,5,8)) end sub </lang>
zkl
<lang zkl>while(1){
digits := [1..4].pump(String,(0).random.fpM("11-",1,9)); exp := ask("Enter an expression using the digits ",digits,
" that evals to 24: ") - " \n";
expf:=exp.apply(fcn(c){if ("1"<=c<="9") "(%s).toFloat()".fmt(c) else c}); reg r; try { Compiler.Compiler.compileText(expf).__constructor(); r=vm.regX } catch { println("bad expression"); continue; } else{ extra := (exp - "+-/*()" - digits); if (extra) { println("Extra goodies in expression: ",extra); continue; } (digits.split("").sort() != (exp - "+-/*()").split("").sort()) : if(_) { println("You can only use the digits ",digits," once each"); continue; }; if (exp.matches("*[1-9][1-9]*"))
{ println("no repeated digits"); continue; }
if (r.closeTo(24,0.001)) "nice!".println(); else println("That evaled to ",r,", not 24"); }
}</lang>
- Output:
Enter an expression using the digits 8833 that evals to 24: (8/(3-(8/3))) nice! Enter an expression using the digits 8833 that evals to 24: (8/(3-(8/9))) Extra goodies in expression: 9 Enter an expression using the digits 8833 that evals to 24: (8/(3-(8/8))) You can only use the digits 8833 once each Enter an expression using the digits 7155 that evals to 24: 7+1+5+5 That evaled to 18, not 24 Enter an expression using the digits 8332 that evals to 24: 8*3*(3-2) nice!
ZX Spectrum Basic
<lang zxbasic>10 LET n$="" 20 RANDOMIZE 30 FOR i=1 TO 4 40 LET n$=n$+STR$ (INT (RND*9)+1) 50 NEXT i 60 LET i$="": LET f$="": LET p$="" 70 CLS 80 PRINT "24 game" 90 PRINT "Allowed characters:" 100 LET i$=n$+"+-*/()" 110 PRINT AT 4,0; 120 FOR i=1 TO 10 130 PRINT i$(i);" "; 140 NEXT i 150 PRINT "(0 to end)" 160 INPUT "Enter the formula";f$ 170 IF f$="0" THEN STOP 180 PRINT AT 6,0;f$;" = "; 190 FOR i=1 TO LEN f$ 200 LET c$=f$(i) 210 IF c$=" " THEN LET f$(i)="": GO TO 250 220 IF c$="+" OR c$="-" OR c$="*" OR c$="/" THEN LET p$=p$+"o": GO TO 250 230 IF c$="(" OR c$=")" THEN LET p$=p$+c$: GO TO 250 240 LET p$=p$+"n" 250 NEXT i 260 RESTORE 270 FOR i=1 TO 11 280 READ t$ 290 IF t$=p$ THEN LET i=11 300 NEXT i 310 IF t$<>p$ THEN PRINT INVERSE 1;"Bad construction!": BEEP 1,.1: PAUSE 0: GO TO 60 320 FOR i=1 TO LEN f$ 330 FOR j=1 TO 10 340 IF (f$(i)=i$(j)) AND f$(i)>"0" AND f$(i)<="9" THEN LET i$(j)=" " 350 NEXT j 360 NEXT i 370 IF i$( TO 4)<>" " THEN PRINT FLASH 1;"Invalid arguments!": BEEP 1,.01: PAUSE 0: GO TO 60 380 LET r=VAL f$ 390 PRINT r;" "; 400 IF r<>24 THEN PRINT FLASH 1;"Wrong!": BEEP 1,1: PAUSE 0: GO TO 60 410 PRINT FLASH 1;"Correct!": PAUSE 0: GO TO 10 420 DATA "nononon" 430 DATA "(non)onon" 440 DATA "nono(non)" 450 DATA "no(no(non))" 460 DATA "((non)on)on" 470 DATA "no(non)on" 480 DATA "(non)o(non)" 485 DATA "no((non)on)" 490 DATA "(nonon)on" 495 DATA "(no(non))on" 500 DATA "no(nonon)"</lang>
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