Loops/Break
You are encouraged to solve this task according to the task description, using any language you may know.
Show a loop which prints random numbers (each number newly generated each loop) from 0 to 19 (inclusive). If a number is 10, stop the loop after printing it, and do not generate any further numbers. Otherwise, generate and print a second random number before restarting the loop. If the number 10 is never generated as the first number in a loop, loop forever.
6502 Assembly
Code is called as a subroutine (i.e. JSR LoopBreakSub). Specific OS/hardware routines for generating random numbers and printing are left unimplemented. <lang 6502asm>LoopBreakSub: PHA ;push accumulator onto stack
BreakLoop: JSR GenerateRandomNum ;routine not implemented
;generates random number and puts in memory location RandomNumber
LDA RandomNumber JSR DisplayAccumulator ;routine not implemented CMP #10 BEQ Break JSR GenerateRandomNum LDA RandomNumber JSR DisplayAccumulator JMP BreakLoop
Break: PLA ;restore accumulator from stack RTS ;return from subroutine</lang>
Ada
<lang Ada>with Ada.Text_IO; use Ada.Text_IO; with Ada.Numerics.Discrete_Random;
procedure Test_Loop_Break is
type Value_Type is range 1..20; package Random_Values is new Ada.Numerics.Discrete_Random (Value_Type); use Random_Values; Dice : Generator; A, B : Value_Type;
begin
loop
A := Random (Dice);
Put_Line (Value_Type'Image (A));
exit when A = 10;
B := Random (Dice);
Put_Line (Value_Type'Image (B));
end loop;
end Test_Loop_Break;</lang>
Aime
<lang aime>integer main(void) {
integer a, b;
while (1) {
a = drand(19);
o_integer(a);
o_byte('\n');
if (a == 10) {
break;
}
b = drand(19);
o_integer(b);
o_byte('\n');
}
return 0;
}</lang>
ALGOL 68
- note: This specimen retains the original C coding style.
<lang algol68>main: (
INT a, b; INT seed := 4; # chosen by a fair dice roll, guaranteed to be random c.f. http://xkcd.com/221/ # # first random; # WHILE a := ENTIER (next random(seed) * 20); print((a)); # WHILE # NOT (a = 10) DO b := ENTIER (next random(seed) * 20); print((b, new line)) OD; print(new line)
)</lang> Sample output:
+13 +6
+1 +8
+13 +2
+1 +12
+0 +12
+14 +8
+9 +2
+19 +13
+0 +4
+8 +14
+17 +7
+11 +9
+7 +8
+2 +1
+11 +2
+13 +18
+3 +7
+11 +17
+4 +13
+16 +12
+19 +17
+9 +7
+8 +5
+4 +8
+7 +5
+0 +18
+8 +13
+7 +4
+10
AutoHotkey
<lang AutoHotkey>Loop {
Random, var, 0, 19 output = %output%`n%var% If (var = 10) Break Random, var, 0, 19 output = %output%`n%var%
} MsgBox % output</lang>
AWK
<lang awk>BEGIN { for (;;) { print n = int(rand() * 20) if (n == 10) break print int(rand() * 20) } }</lang>
BASIC
<lang qbasic>do
a = int(rnd * 20) print a if a = 10 then exit loop 'EXIT FOR works the same inside FOR loops b = int(rnd * 20) print b
loop</lang>
ZX Spectrum Basic
On the ZX Spectrum, for loops must be terminated through the NEXT statement, otherwise a memory leak will occur. To terminate a loop prematurely, set the loop counter to the last iterative value and jump to the NEXT statement:
<lang zxbasic> 10 FOR l = 1 TO 20 20 IF l = 10 THEN LET l = 20: GO TO 40: REM terminate the loop 30 PRINT l 40 NEXT l 50 STOP </lang>
Batch File
<lang dos>@echo off
- loop
set /a N=%RANDOM% %% 20 echo %N% if %N%==10 exit /b
goto loop</lang>
bc
<lang bc>s = 1 /* seed of the random number generator */ scale = 0
/* Random number from 0 to 20. */ define r() { auto a while (1) { /* Formula (from POSIX) for random numbers of low quality. */ s = (s * 1103515245 + 12345) % 4294967296 a = s / 65536 /* a in [0, 65536) */ if (a >= 16) break /* want a >= 65536 % 20 */ } return (a % 20) }
while (1) {
n = r()
n /* print 1st number */
if (n == 10) break
r() /* print 2nd number */
}
quit</lang>
C
<lang c>#include <stdlib.h>
- include <time.h>
- include <stdio.h>
int main() {
int a, b;
srand(time(NULL));
while (1) {
a = rand() % 20; /* not exactly uniformly distributed, but doesn't matter */
printf("%d\n", a);
if (a == 10) break;
b = rand() % 20; /* not exactly uniformly distributed, but doesn't matter */
printf("%d\n", b);
}
return 0;
}</lang>
C#
<lang csharp>class Program {
static void Main(string[] args)
{
Random random = new Random();
while (true)
{
int a = random.Next(20);
Console.WriteLine(a);
if (a == 10)
break;
int b = random.Next(20)
Console.WriteLine(b);
}
Console.ReadLine();
}
}</lang>
C++
<lang cpp>#include <iostream>
- include <ctime>
- include <cstdlib>
int main() {
srand(time(0));
while(true)
{
int a = 0 + rand() % 19;
std::cout << a << std::endl;
if (a == 10)
break;
int b = 0 + rand() % 19;
std::cout << b << std::endl;
}
return 0;
}</lang>
Chef
"Liquify" is now depreciated in favor of "Liquefy", but my interpreter/compiler (Acme::Chef) works only with "Liquify" so that's how I'm leaving it. At least it'll work no matter which version you use.
<lang Chef>Healthy Vita-Sauce Loop - Broken.
Makes a whole lot of sauce for two people.
Ingredients. 0 g Vitamin A 1 g Vitamin B 2 g Vitamin C 3 g Vitamin D 4 g Vitamin E 5 g Vitamin F 6 g Vitamin G 7 g Vitamin H 8 g Vitamin I 9 g Vitamin J 10 g Vitamin K 11 g Vitamin L 12 g Vitamin M 13 g Vitamin N 14 g Vitamin O 15 g Vitamin P 16 g Vitamin Q 17 g Vitamin R 18 g Vitamin S 19 g Vitamin T 20 g Vitamin U 21 g Vitamin V 22 g Vitamin W 32 g Vitamin X 24 g Vitamin Y 25 g Vitamin Z
Method. Liquify Vitamin X. Put Vitamin N into 1st mixing bowl. Fold Vitamin Y into 1st mixing bowl. Liquify Vitamin Y. Clean 1st mixing bowl. Put Vitamin K into 1st mixing bowl. Fold Vitamin Z into 1st mixing bowl. Liquify Vitamin Z. Clean 1st mixing bowl. Put Vitamin Y into 4th mixing bowl. Put Vitamin Z into 4th mixing bowl. Pour contents of the 4th mixing bowl into the 2nd baking dish. Put Vitamin A into 2nd mixing bowl. Put Vitamin B into 2nd mixing bowl. Put Vitamin C into 2nd mixing bowl. Put Vitamin D into 2nd mixing bowl. Put Vitamin E into 2nd mixing bowl. Put Vitamin F into 2nd mixing bowl. Put Vitamin G into 2nd mixing bowl. Put Vitamin H into 2nd mixing bowl. Put Vitamin I into 2nd mixing bowl. Put Vitamin J into 2nd mixing bowl. Put Vitamin K into 2nd mixing bowl. Put Vitamin L into 2nd mixing bowl. Put Vitamin M into 2nd mixing bowl. Put Vitamin N into 2nd mixing bowl. Put Vitamin O into 2nd mixing bowl. Put Vitamin P into 2nd mixing bowl. Put Vitamin Q into 2nd mixing bowl. Put Vitamin R into 2nd mixing bowl. Put Vitamin S into 2nd mixing bowl. Put Vitamin T into 2nd mixing bowl. Verb the Vitamin V. Mix the 2nd mixing bowl well. Fold Vitamin U into 2nd mixing bowl. Put Vitamin U into 3rd mixing bowl. Remove Vitamin K from 3rd mixing bowl. Fold Vitamin V into 3rd mixing bowl. Put Vitamin X into 1st mixing bowl. Put Vitamin V into 1st mixing bowl. Verb until verbed. Pour contents of the 1st mixing bowl into the 1st baking dish.
Serves 2.</lang>
Clojure
<lang lisp>(loop [[a b & more] (repeatedly #(rand-int 20))]
(println a) (when-not (= 10 a) (println b) (recur more)))</lang>
Common Lisp
<lang lisp>(loop
(setq a (random 20))
(print a)
(if (= a 10)
(return))
(setq b (random 20))
(print b))</lang>
D
<lang d>import std.stdio, std.random;
void main() {
while (true) {
int r = uniform(0, 20);
write(r, " ");
if (r == 10)
break;
write(uniform(0, 20), " ");
}
}</lang> One output:
2 4 9 5 3 7 4 4 14 14 3 7 13 8 13 6 10
dc
<lang dc>1 ss [s = seed of the random number generator]sz 0k [scale = 0]sz
[Function r: Push a random number from 0 to 20.]sz [
[2Q]SA [ [Formula (from POSIX) for random numbers of low quality.]sz ls 1103515245 * 12345 + 4294967296 % d ss [Compute next s]sz 65536 / [it = s / 65536]sz d 16 !>A [Break loop if 16 <= it]sz sz 0 0 =B [Forget it, continue loop]sz ]SB 0 0 =B 20 % [Push it % 20]sz LA sz LB sz [Restore A, B]sz
]sr
[2Q]sA
[
0 0 =r p [Print 1st number.]sz 10 =A [Break if 10 == it.]sz 0 0 =r p sz [Print 2nd number.]sz 0 0 =B [Continue loop.]sz
]sB 0 0 =B</lang>
Delphi
<lang Delphi>program Project5;
{$APPTYPE CONSOLE}
var
num:Integer;
begin
Randomize; while true do begin num:=Random(20); Writeln(num); if num=10 then break; end;
end.
</lang>
DWScript
<lang delphi> while True do begin
var num := RandomInt(20); PrintLn(num); if num=10 then Break;
end;</lang>
E
<lang e>while (true) {
def a := entropy.nextInt(20)
print(a)
if (a == 10) {
println()
break
}
println(" ", entropy.nextInt(20))
}</lang>
Ela
This implementation uses .NET Framework Math.Randomize function. Current ticks multiplied by an iteration index are used as a seed. As a result an output looks almost truly random:
<lang ela>open DateTime open Core open Con
let loop = loop' 1
where loop' n t | r == t = writen r
| else = writen r $ loop' (n+1) t
where seed = (ticks <| now!) * n
et r = rnd seed 0 19
loop 10</lang>
Euphoria
<lang euphoria>integer i while 1 do
i = rand(20) - 1
printf(1, "%g ", {i})
if i = 10 then
exit
end if
printf(1, "%g ", {rand(20)-1})
end while</lang>
The rand() function returns a random integer from 1 to the integer provided.
Factor
Using with-return:
<lang factor>[
[ 20 random [ . ] [ 10 = [ return ] when ] bi 20 random . t ] loop
] with-return</lang>
Idiomatic Factor: <lang factor>[ 20 random [ . ] [ 10 = not ] bi 20 random . ] loop</lang>
Fantom
<lang fantom> class ForBreak {
public static Void main ()
{
while (true)
{
a := Int.random(0..19)
echo (a)
if (a == 10) break
echo (Int.random(0..19))
}
}
} </lang>
Forth
<lang forth>include random.fs
- main
begin 20 random dup . 10 <> while 20 random . repeat ;
\ use LEAVE to break out of a counted loop
- main
100 0 do i random dup . 10 = if leave then i random . loop ;</lang>
Fortran
<lang fortran>program Example
implicit none
real :: r integer :: a, b
do
call random_number(r)
a = int(r * 20)
write(*,*) a
if (a == 10) exit
call random_number(r)
b = int(r * 20)
write(*,*) b
end do
end program Example</lang>
<lang fortran> PROGRAM LOOPBREAK
INTEGER I, RNDINT
C It doesn't matter what number you put here.
CALL SDRAND(123)
C Because FORTRAN 77 semantically lacks many loop structures, we C have to use GOTO statements to do the same thing.
10 CONTINUE
C Print a random number.
I = RNDINT(0, 19)
WRITE (*,*) I
C If the random number is ten, break (i.e. skip to after the end C of the "loop").
IF (I .EQ. 10) GOTO 20
C Otherwise, print a second random number.
I = RNDINT(0, 19)
WRITE (*,*) I
C This is the end of our "loop," meaning we jump back to the C beginning again.
GOTO 10
20 CONTINUE
STOP
END
C FORTRAN 77 does not have come with a random number generator, but it C is easy enough to type "fortran 77 random number generator" into your C preferred search engine and to copy and paste what you find. The C following code is a slightly-modified version of: C C http://www.tat.physik.uni-tuebingen.de/ C ~kley/lehre/ftn77/tutorial/subprograms.html
SUBROUTINE SDRAND (IRSEED)
COMMON /SEED/ UTSEED, IRFRST
UTSEED = IRSEED
IRFRST = 0
RETURN
END
INTEGER FUNCTION RNDINT (IFROM, ITO)
INTEGER IFROM, ITO
PARAMETER (MPLIER=16807, MODLUS=2147483647, &
& MOBYMP=127773, MOMDMP=2836)
COMMON /SEED/ UTSEED, IRFRST
INTEGER HVLUE, LVLUE, TESTV, NEXTN
SAVE NEXTN
IF (IRFRST .EQ. 0) THEN
NEXTN = UTSEED
IRFRST = 1
ENDIF
HVLUE = NEXTN / MOBYMP
LVLUE = MOD(NEXTN, MOBYMP)
TESTV = MPLIER*LVLUE - MOMDMP*HVLUE
IF (TESTV .GT. 0) THEN
NEXTN = TESTV
ELSE
NEXTN = TESTV + MODLUS
ENDIF
IF (NEXTN .GE. 0) THEN
RNDINT = MOD(MOD(NEXTN, MODLUS), ITO - IFROM + 1) + IFROM
ELSE
RNDINT = MOD(MOD(NEXTN, MODLUS), ITO - IFROM + 1) + ITO + 1
ENDIF
RETURN
END</lang>
GAP
<lang gap>while true do
a := Random(0, 19);
Print(a);
if a = 10 then
Print("\n");
break;
fi;
a := Random(0, 19);
Print("\t", a, "\n");
od;
- 11 6
- 5 8
- 1 4
- 5 10
- 1 16
- 10</lang>
GML
<lang GML>while(1)
{
a = floor(random(19))
show_message(string(a))
if(a = 10)
break
b = floor(random(19))
show_message(string(a))
}
</lang>
Go
<lang go>package main
import "fmt" import "math/rand" import "time"
func main() {
rand.Seed(time.Now().UnixNano())
for {
a := rand.Intn(20)
fmt.Println(a)
if a == 10 {
break
}
b := rand.Intn(20)
fmt.Println(b)
}
}</lang>
Groovy
<lang groovy>final random = new Random()
while (true) {
def random1 = random.nextInt(20) print random1 if (random1 == 10) break print ' ' println random.nextInt(20)
}</lang>
Haskell
<lang haskell>import Control.Monad import System.Random
loopBreak n k = do
r <- randomRIO (0,n) print r unless (r==k) $ do print =<< randomRIO (0,n) loopBreak n k</lang>
Use: <lang haskell>loopBreak 19 10</lang>
HicEst
<lang hicest>1 DO i = 1, 1E20 ! "forever"
a = INT( RAN(10, 10) )
WRITE(name) a
IF( a == 10) GOTO 10
b = INT( RAN(10, 10) )
WRITE(name) b
ENDDO
10
END</lang>
Icon and Unicon
<lang Icon>procedure main()
while 10 ~= writes(?20-1) do write(", ",?20-1)
end</lang> Notes:
- For any positive integer i, ?i produces a value j where 1 <= j <= i
- Although this can be written with a break (e.g. repeat expression & break), there is no need to actually use one. (And it's ugly).
- Programmers new to Icon/Unicon need to understand that just about everything returns values including comparison operators, I/O functions like write/writes.
- This program will perform similarly but not identically under Icon and Unicon because the random operator ?i behaves differently. While both produce pseudo-random numbers a different generator is used. Also, the sequence produced by Icon begins with the same seed value and is repeatable whereas the sequence produced by Unicon does not. One way to force Icon to use different random sequences on each call would be to add the line <lang Icon>&random := integer(map("smhSMH","Hh:Mm:Ss",&clock))</lang> at the start of the main procedure to set the random number seed based on the time of day.
J
<lang j>loopexample=: verb define
while. 1 do. smoutput n=. ?20 if. 10=n do. return. end. smoutput ?20 end.
)</lang>
Note that break. could have been used in place of return..
Java
<lang java>import java.util.Random;
Random rand = new Random(); while(true){
int a = rand.nextInt(20); System.out.println(a); if(a == 10) break; int b = rand.nextInt(20); System.out.println(b);
}</lang>
JavaScript
<lang javascript>for (;;) {
var a = Math.floor(Math.random() * 20); print(a); if (a == 10) break; a = Math.floor(Math.random() * 20); print(a);
}</lang>
The print() function is available in the Rhino JavaScript shell.
Liberty BASIC
The task specifies a "number". <lang lb>while num<>10
num=rnd(1)*20 print num if num=10 then exit while print rnd(1)*20
wend </lang>If "integer" was meant, this code fulfils that requirement. <lang lb>while num<>10
num=int(rnd(1)*20) print num if num=10 then exit while print int(rnd(1)*20)
wend </lang>
Lisaac
<lang Lisaac>Section Header
+ name := TEST_LOOP_BREAK;
Section Public
- main <- (
+ a, b : INTEGER;
`srand(time(NULL))`;
{
a := `rand()`:INTEGER % 20; // not exactly uniformly distributed, but doesn't matter
a.print;
'\n'.print;
a == 10
}.until_do {
b := `rand()`:INTEGER % 20; // not exactly uniformly distributed, but doesn't matter
b.print;
'\n'.print;
}
);</lang>
Lua
<lang lua>repeat
k = math.random(19) print(k) if k == 10 then break end print(math.random(19)
until false</lang>
Mathematica
<lang Mathematica>While[(Print[#];#!=10)&[RandomIntger[{0,19}]],
Print[RandomInteger[{0,19}]
]</lang>
M4
<lang M4>define(`randSeed',141592653)dnl define(`setRand',
`define(`randSeed',ifelse(eval($1<10000),1,`eval(20000-$1)',`$1'))')dnl
define(`rand_t',`eval(randSeed^(randSeed>>13))')dnl define(`random',
`define(`randSeed',eval((rand_t^(rand_t<<18))&0x7fffffff))randSeed')dnl
dnl define(`loopbreak',`define(`a',eval(random%20))`a='a ifelse(a,10,`',`define(`b',eval(random%20))`b='b loopbreak')')dnl dnl loopbreak</lang>
Output:
a=17 b=3 a=0 b=15 a=10
Modula-3
<lang modula3>MODULE Break EXPORTS Main;
IMPORT IO, Fmt, Random;
VAR a,b: INTEGER;
BEGIN
WITH rand = NEW(Random.Default).init() DO
LOOP
a := rand.integer(min := 0, max := 19);
IO.Put(Fmt.Int(a) & "\n");
IF a = 10 THEN EXIT END;
b := rand.integer(min := 0, max := 19);
IO.Put(Fmt.Int(b) & "\n");
END;
END;
END Break.</lang>
MOO
<lang moo>while (1)
a = random(20) - 1; player:tell(a); if (a == 10) break; endif b = random(20) - 1; player:tell(b);
endwhile</lang>
MUMPS
<lang MUMPS>BREAKLOOP
NEW A,B SET A="" FOR Q:A=10 DO .SET A=$RANDOM(20) .WRITE !,A .Q:A=10 .SET B=$RANDOM(20) .WRITE ?6,B KILL A,B QUIT ;A denser version that doesn't require two tests NEW A,B FOR SET A=$RANDOM(20) WRITE !,A QUIT:A=10 SET B=$RANDOM(20) WRITE ?6,B KILL A,B QUIT</lang>
Output:
USER>D BREAKLOOP^ROSETTA 5 3 9 13 3 12 9 19 16 4 11 17 18 2 4 18 10 USER>D BREAKLOOP+11^ROSETTA 6 13 15 3 0 8 8 18 7 13 15 10 15 13 10
Nemerle
<lang Nemerle>using System; using System.Console; using Nemerle.Imperative;
module Break {
Main() : void
{
def rnd = Random();
while (true)
{
def a = rnd.Next(20);
WriteLine(a);
when (a == 10) break;
def b = rnd.Next(20);
WriteLine(b);
}
}
}</lang>
NetRexx
<lang NetRexx>/* NetRexx */ options replace format comments java crossref savelog symbols nobinary
say say 'Loops/Break' rn = Rexx rnd = Random()
loop label lb forever rn = rnd.nextInt(19) say rn.right(3)'\-' if rn = 10 then leave lb rn = rnd.nextInt(19) say rn.right(3)'\-' end lb say
</lang>
Objeck
<lang objeck> while(true) {
a := (Float->Random() * 20.0)->As(Int);
a->PrintLine();
if(a = 10) {
break;
};
a := (Float->Random() * 20.0)->As(Int);
a->PrintLine();
} </lang>
OCaml
<lang ocaml># Random.self_init();; - : unit = ()
- while true do
let a = Random.int 20 in print_int a; print_newline(); if a = 10 then raise Exit; let b = Random.int 20 in print_int b; print_newline() done;;
15 18 2 13 10 Exception: Pervasives.Exit.</lang>
Octave
<lang octave>while(1)
a = floor(unifrnd(0,20, 1)); disp(a) if ( a == 10 ) break endif b = floor(unifrnd(0,20, 1)); disp(b)
endwhile</lang>
Oz
We can implement this either with recursion or with a special type of the for-loop. Both can be considered idiomatic. <lang oz>for break:Break do
R = {OS.rand} mod 20
in
{Show R}
if R == 10 then {Break}
else {Show {OS.rand} mod 20}
end
end</lang>
PARI/GP
<lang parigp>while(1,
t=random(20); print(t); if(t==10, break); print(random(20))
)</lang>
Pascal
See Delphi
Perl
<lang perl>while (1) {
my $a = int(rand(20));
print "$a\n";
if ($a == 10) {
last;
}
my $b = int(rand(20));
print "$b\n";
}</lang>
Perl 6
<lang perl6>loop {
say my $n = (0..19).pick; last if $n == 10; say (0..19).pick;
}</lang>
PHP
<lang php>while (true) {
$a = rand(0,19);
echo "$a\n";
if ($a == 10)
break;
$b = rand(0,19);
echo "$b\n";
}</lang>
PicoLisp
Literally: <lang PicoLisp>(use R
(loop
(println (setq R (rand 1 19)))
(T (= 10 R))
(println (rand 1 19)) ) )</lang>
Shorter: <lang PicoLisp>(until (= 10 (println (rand 1 19)))
(println (rand 1 19)) )</lang>
Pike
<lang pike>int main(){
while(1){
int a = random(20);
write(a + "\n");
if(a == 10){
break;
}
int b = random(20);
write(b + "\n");
}
}</lang>
PL/I
<lang PL/I> do forever;
k = random()*19; put (k); if k = 10 then leave; k = random()*19; put skip list (k);
end; </lang>
PostScript
<lang postscript>realtime srand % init RNG {
rand 20 mod % generate number between 0 and 19
dup = % print it
10 eq { exit } if % exit if 10
} loop</lang>
PowerShell
<lang powershell>$r = New-Object Random for () {
$n = $r.Next(20)
Write-Host $n
if ($n -eq 10) {
break
}
Write-Host $r.Next(20)
}</lang>
PureBasic
<lang PureBasic>If OpenConsole()
Repeat
a = Random(19)
PrintN(Str(a))
If a = 10
Break
EndIf
b = Random(19)
PrintN(Str(b))
PrintN("")
ForEver
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit") Input() CloseConsole()
EndIf</lang>
Python
<lang python>import random
while True:
a = random.randrange(20)
print a
if a == 10:
break
b = random.randrange(20)
print b</lang>
R
<lang R>sample0to19 <- function() sample(0L:19L, 1,replace=TRUE) repeat {
result1 <- sample0to19()
if (result1 == 10L)
{
print(result1)
break
}
result2 <- sample0to19()
cat(result1, result2, "\n")
}</lang>
Qi
<lang qi> (define loop -> (if (= 10 (PRINT (random 20)))
true
(do (PRINT (random 20))
(loop))))
(loop) </lang>
REBOL
<lang REBOL>REBOL [ Title: "Loop/Break" Author: oofoe Date: 2009-12-19 URL: http://rosettacode.org/wiki/Loop/Break ]
random/seed 1 ; Make repeatable.
- random/seed now ; Uncomment for 'true' randomness.
r20: does [(random 20) - 1]
forever [ prin x: r20 if 10 = x [break] print rejoin [" " r20] ] print ""</lang>
Output:
14 11 19 15 6 11 12 11 3 14 10
Retro
<lang Retro>doc{ A couple of helper functions to make the rest of the code more readable. }doc
- rand ( -n ) random 20 mod ;
- . ( n- ) putn space ;
doc{ One approach is to use a simple repeat/again loop, and a conditional exit. For instance: }doc
- foo ( - )
repeat rand dup . 10 = if; rand . again ;
doc{ The other approach uses a structured while loop with the second printing handled by a conditional clause. }doc
[ rand dup . 10 <> [ [ rand . ] ifTrue ] sip ] while </lang>
REXX
<lang rexx>do forever
a = random(19) say a if a = 10 then leave b = random(19) say b
end</lang>
Ruby
<lang ruby>loop do
a = rand(20)
puts a
if a == 10
break
end
b = rand(20)
puts b
end</lang>
Sather
<lang sather>-- help class for random number sequence class RANDOM is
attr seed:INT;
create(seed:INT):SAME is res:RANDOM := new; res.seed := seed; return res; end; -- this code is taken from rand's man (C) next:INT is seed := seed * 1103515245 + 12345; return (seed/65536) % 32768; end;
end;
class MAIN is
main is
a, b :INT;
rnd:RANDOM := #(1);
loop
a := rnd.next % 20;
#OUT + a + "\n";
if a = 10 then break!; end; -- here we break
b := rnd.next % 20;
#OUT + b + "\n";
end;
end;
end;</lang>
Scala
A break library method is available in Scala 2.8 but not 2.7
<lang Scala> import scala.util.Random
val rand = new Random var doNext = true
while(doNext) {
val first = rand.nextInt(20) println(first)
if (first != 10) {
val second = rand.nextInt(20)
println(second)
} else {
doNext = false
}
} </lang>
Scheme
<lang scheme> (let loop ((first (random 20)))
(print first)
(if (not (= first 10))
(begin
(print (random 20))
(loop (random 20)))))
</lang>
Or by using call/cc to break out:
<lang scheme> (call/cc
(lambda (break)
(let loop ((first (random 20)))
(print first)
(if (= first 10)
(break))
(print (random 20))
(loop (random 20)))))
</lang>
SNOBOL4
Most Snobols lack a built-in rand( ) function. Kludgy "Linux-only" implementation: <lang snobol> input(.random,io_findunit(),1,"/dev/urandom") while &ALPHABET random @rand output = rand = rand - (rand / 20) * 20 eq(rand,10) :f(while) end</lang>
Or using a library function:
<lang SNOBOL4>* rand(n) -> real x | 0 <= x < n -include 'random.sno'
loop ne(output = convert(rand(20)'integer'),10) :s(loop) end</lang>
Suneido
<lang Suneido>forever
{
Print(i = Random(20))
if i is 10
break
Print(i = Random(20))
}
</lang>
Tcl
<lang tcl>while true {
set a [expr int(20*rand())]
puts $a
if {$a == 10} {
break
}
set b [expr int(20*rand())]
puts $b
}</lang>
TI-89 BASIC
<lang ti89b>Local x Loop
rand(20)-1 → x Disp x © new line and text If x = 10 Then Exit EndIf Output 64, 50, rand(20)-1 © paint text to the right on same line
EndLoop</lang>
TorqueScript
<lang Torque>for(%a = 0; %a > -1; %a++) {
%number = getRand(0, 19);
if(%number == 10)
break;
}</lang>
TUSCRIPT
<lang tuscript> $$ MODE TUSCRIPT LOOP a=RANDOM_NUMBERS (0,19,1) IF (10==a) THEN
PRINT "a=",a STOP
ELSE
b=RANDOM_NUMBERS (0,19,1) PRINT "a=",a," b=",b
ENDIF IF (10==a,b) STOP ENDLOOP </lang> Output:
a=0 b=17 a=11 b=13 a=3 b=16 a=17 b=13 a=8 b=11 a=8 b=0 a=6 b=2 a=10
UNIX Shell
This script gets random numbers from jot(1). If there is any error with jot(1), the script exits.
<lang bash>while true; do a=`jot -w %d -r 1 0 20` || exit $? echo $a test 10 -eq $a && break b=`jot -w %d -r 1 0 20` || exit $? echo $b done</lang>
Korn Shells have a RANDOM parameter.
<lang bash>while true; do
echo $((a=RANDOM%20)) [ $a -eq 10 ] && break echo $((b=RANDOM%20))
done</lang>
VBScript
Implementation
Based on BASIC version. Demonstrates breaking out of do/loop and for/next (Exit is good for getting out of functions and subs as well)
<lang vb> do a = int( rnd * 20) wscript.stdout.write a if a = 10 then exit do b = int( rnd * 20 ) wscript.echo vbnullstring,b loop
dim i for i = 1 to 100000 a = int( rnd * 20) wscript.stdout.write a if a = 10 then exit for b = int( rnd * 20 ) wscript.echo vbnullstring,b next </lang>
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