Roman numerals/Encode
Create a function taking a positive integer as its parameter and returning a string containing the Roman numeral representation of that integer. Modern Roman numerals are written by expressing each digit separately, starting with the left most digit and skipping any digit with a value of zero.
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
In Roman numerals:
- 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC
- 2008 is written as 2000=MM, 8=VIII; or MMVIII
- 1666 uses each Roman symbol in descending order: MDCLXVI
11l
<lang 11l>V anums = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1] V rnums = ‘M CM D CD C XC L XL X IX V IV I’.split(‘ ’)
F to_roman(=x)
V ret = ‘’
L(a, r) zip(:anums, :rnums)
(V n, x) = divmod(x, a)
ret ‘’= r * n
R ret
V test = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 40,
50, 60, 69, 70, 80, 90, 99, 100, 200, 300, 400, 500, 600, 666, 700, 800, 900, 1000,
1009, 1444, 1666, 1945, 1997, 1999, 2000, 2008, 2010, 2011, 2500, 3000, 3999]
L(val) test
print(val‘ - ’to_roman(val))</lang>
8080 Assembly
<lang 8080asm> org 100h jmp test ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; Takes a 16-bit integer in HL, and stores it ;; as a 0-terminated string starting at BC. ;; On exit, all registers destroyed; BC pointing at ;; end of string. mkroman: push h ; put input on stack lxi h,mkromantab mkromandgt: mov a,m ; scan ahead to next entry ana a inx h jnz mkromandgt xthl ; load number mov a,h ; if zero, we're done ora l jz mkromandone xthl ; load next entry from table mov e,m ; de = number inx h mov d,m inx h xthl ; load number xra a ; find how many we need subtract: inr a ; with trial subtraction dad d jc subtract push psw ; keep counter mov a,d ; we subtracted one too many cma ; so we need to add one back mov d,a mov a,e cma mov e,a inx d dad d pop d ; restore counter (into D) xthl ; load table pointer stringouter: dcr d ; do we need to include one? jz mkromandgt push h ; keep string location stringinner: mov a,m ; copy string into target stax b ana a ; done yet? jz stringdone inx h inx b ; copy next character jmp stringinner stringdone: pop h ; restore string location jmp stringouter mkromandone: pop d ; remove temporary variable from stack ret mkromantab: db 0 db 18h,0fch,'M',0 ; The value for each entry db 7ch,0fch,'CM',0 ; is stored already negated db 0ch,0feh,'D',0 ; so that it can be immediately db 70h,0feh,'CD',0 ; added using `dad'. db 9ch,0ffh,'C',0 ; This also has the convenient db 0a6h,0ffh,'XC',0 ; property of not having any db 0ceh,0ffh,'L',0 ; zero bytes except the string db 0d8h,0ffh,'XL',0 ; and row terminators. db 0f6h,0ffh,'X',0 db 0f7h,0ffh,'IX',0 db 0fbh,0ffh,'V',0 db 0fch,0ffh,'IV',0 db 0ffh,0ffh,'I',0 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; Test code test: mvi c,10 ; read string from console lxi d,dgtbufdef call 5 lxi h,0 ; convert to integer lxi b,dgtbuf readdgt: ldax b ana a jz convert dad h ; hl *= 10 mov d,h mov e,l dad h dad h dad d sui '0' mov e,a mvi d,0 dad d inx b jmp readdgt convert: lxi b,romanbuf ; convert to roman call mkroman mvi a,'$' ; switch string terminator stax b mvi c,9 ; output result lxi d,romanbuf jmp 5 nl: db 13,10,'$' dgtbufdef: db 5,0 dgtbuf: ds 6 romanbuf:</lang>
8086 Assembly
Main and Supporting Functions
The main program and test values: 70,1776,2021,3999,4000 <lang asm> mov ax,0070h call EncodeRoman mov si,offset StringRam call PrintString call NewLine
mov ax,1776h call EncodeRoman mov si,offset StringRam call PrintString call NewLine
mov ax,2021h call EncodeRoman mov si,offset StringRam call PrintString call NewLine
mov ax,3999h call EncodeRoman mov si,offset StringRam call PrintString call NewLine
mov ax,4000h call EncodeRoman mov si,offset StringRam
ReturnToDos ;macro that calls the int that exits dos</lang>
The EncodeRoman routine:
<lang asm>;ROMAN NUMERALS MODULE
EncodeRoman:
- takes a BCD value in AX and stores its Roman numeral equivalent in ram.
call UnpackBCD
cmp dh,03h jng continue_EncodeRoman ;roman numerals only go up to 3999. jmp errorhandler_encodeRoman_inputTooBig continue_EncodeRoman: mov si,offset StringRam ;using SI as destination of roman numerals. push ax push cx mov ch,0 mov cl,dh ;loop counter cmp dh,0 jz skipThousands encodeRoman_handleThousands: mov al,"M" mov [ds:si],al ;store in string ram inc si ; call PrintChar loop encodeRoman_handleThousands skipThousands: pop cx pop ax
encodeRoman_HandleHundreds: pushall mov bh,0 mov bl,dl ;use bx as an offset into Roman_Lookup_Master SHL bl,1 SHL bl,1 ;multiply by 2, we are indexing into a table with 4 bytes per row. mov di,offset Roman_Lookup_Master mov cx,4 getChar_Hundreds: mov al,[bx+es:di] ;get first char index push bx push di mov di,offset Roman_Hund mov bl,al mov al,[bx+es:di] cmp al,0 jz skipNullChar_RomanHund mov [ds:si],al ;store in ram inc si ; call PrintChar skipNullChar_RomanHund: pop di pop bx inc di loop getChar_Hundreds popall
encodeRoman_HandleTens:
pushall
mov bh,0
mov bl,ah ;use bx as an offset into Roman_Lookup_Master
SHL bl,1
SHL bl,1 ;multiply by 2, we are indexing into a table with 4 bytes per row.
mov di,offset Roman_Lookup_Master
mov cx,4
getChar_Tens:
mov al,[bx+es:di] ;get first char index
push bx
push di
mov di,offset Roman_Tens
mov bl,al
mov al,[bx+es:di]
cmp al,0
jz skipNullChar_RomanTens
mov [ds:si],al ;store in ram
inc si
; call PrintChar
skipNullChar_RomanTens:
pop di
pop bx
inc di
loop getChar_Tens
popall
encodeRoman_HandleOnes: pushall mov bh,0 mov bl,al ;use bx as an offset into Roman_Lookup_Master SHL bl,1 SHL bl,1 ;multiply by 2, we are indexing into a table with 4 bytes per row. mov di,offset Roman_Lookup_Master mov cx,4 getChar_Ones: mov al,[bx+es:di] ;get first char index push bx push di mov di,offset Roman_Ones mov bl,al mov al,[bx+es:di] cmp al,0 jz skipNullChar_RomanOnes mov [ds:si],al ;store in ram inc si ; call PrintChar skipNullChar_RomanOnes: pop di pop bx inc di loop getChar_Ones popall
mov al,0 mov [ds:si],al ;place a null terminator at the end of the string. ret
errorhandler_encodeRoman_inputTooBig:
push ds
push ax
LoadSegment ds,ax,@data
mov al,01h
mov byte ptr [ds:error_code],al
mov ax, offset EncodeRoman
mov word ptr [ds:error_routine],ax
LoadSegment ds,ax,@code mov si,offset Roman_Error call PrintString pop ax pop ds stc ;set carry, allowing program to branch if error occurred. ret
Roman_Lookup_Master db 0,0,0,0 ;0 db 0,0,0,1 ;1 db 0,0,1,1 ;2 db 0,1,1,1 ;3 db 0,0,1,2 ;4 db 0,0,0,2 ;5 db 0,0,2,1 ;6 db 0,2,1,1 ;7 db 2,1,1,1 ;8 db 0,0,1,3 ;9
Roman_Ones db 0,"IVX" ;the same pattern is used regardless of what power of 10 we're working with Roman_Tens db 0,"XLC" Roman_Hund db 0,"CDM"
Roman_Error db "ERROR: BAD INPUT",0
UnpackBCD:
- converts a "packed" BCD value in AX to an "unpacked" value in DX.AX
- DX is the high byte, AX is the low byte.
- CLOBBERS DX AND AX.
mov dx,0 mov dl,ah mov ah,0 push cx mov cl,4 rol dx,cl ;BEFORE: DX = 00XYh ;AFTER: DX = 0XY0h ror dl,cl ;DX = 0X0Yh
rol ax,cl ;BEFORE: AX = 00XYh ;AFTER: AX = 0XY0h ror al,cl ;AX = 0X0Yh pop cx ret</lang>
Macros used: <lang asm>pushall macro push ax push bx push cx push dx push ds push es push di
- I forgot SI in this macro, but once you add it in the code stops working! So I left it out.
endm
popall macro pop di pop es pop ds pop dx pop cx pop bx pop ax endm</lang>
Output
- Output:
LXX MDCCLXXVI MMXXI MMMCMXCIX ERROR: BAD INPUT
Action!
<lang Action!>DEFINE PTR="CARD" CARD ARRAY arabic=[1000 900 500 400 100 90 50 40 10 9 5 4 1] PTR ARRAY roman(13)
PROC InitRoman()
roman(0)="M" roman(1)="CM" roman(2)="D" roman(3)="CD" roman(4)="C" roman(5)="XC" roman(6)="L" roman(7)="XL" roman(8)="X" roman(9)="IX" roman(10)="V" roman(11)="IV" roman(12)="I"
RETURN
PROC EncodeRomanNumber(CARD n CHAR ARRAY res)
BYTE i,len CHAR ARRAY tmp
res(0)=0 len=0
FOR i=0 TO 12
DO
WHILE arabic(i)<=n
DO
tmp=roman(i)
SAssign(res,tmp,len+1,len+1+tmp(0))
len==+tmp(0)
n==-arabic(i)
OD
OD
res(0)=len
RETURN
PROC Main()
CARD ARRAY data=[1990 2008 5555 1666 3888 3999] BYTE i CHAR ARRAY r(20)
InitRoman()
FOR i=0 TO 5
DO
EncodeRomanNumber(data(i),r)
PrintF("%U=%S%E",data(i),r)
OD
RETURN</lang>
- Output:
Screenshot from Atari 8-bit computer
1990=MCMXC 2008=MMVIII 5555=MMMMMDLV 1666=MDCLXVI 3888=MMMDCCCLXXXVIII 3999=MMMCMXCIX
ActionScript
<lang ActionScript>function arabic2roman(num:Number):String { var lookup:Object = {M:1000, CM:900, D:500, CD:400, C:100, XC:90, L:50, XL:40, X:10, IX:9, V:5, IV:4, I:1}; var roman:String = "", i:String; for (i in lookup) { while (num >= lookup[i]) { roman += i; num -= lookup[i]; } } return roman; } trace("1990 in roman is " + arabic2roman(1990)); trace("2008 in roman is " + arabic2roman(2008)); trace("1666 in roman is " + arabic2roman(1666)); </lang>
- Output:
1990 in roman is MCMXC 2008 in roman is MMVIII 1666 in roman is MDCLXVI
And the reverse: <lang ActionScript>function roman2arabic(roman:String):Number { var romanArr:Array = roman.toUpperCase().split(); var lookup:Object = {I:1, V:5, X:10, L:50, C:100, D:500, M:1000}; var num:Number = 0, val:Number = 0; while (romanArr.length) { val = lookup[romanArr.shift()]; num += val * (val < lookup[romanArr[0]] ? -1 : 1); } return num; } trace("MCMXC in arabic is " + roman2arabic("MCMXC")); trace("MMVIII in arabic is " + roman2arabic("MMVIII")); trace("MDCLXVI in arabic is " + roman2arabic("MDCLXVI"));</lang>
- Output:
MCMXC in arabic is 1990 MMVIII in arabic is 2008 MDCLXVI in arabic is 1666
Ada
<lang ada>with Ada.Text_IO; use Ada.Text_IO;
procedure Roman_Numeral_Test is
function To_Roman (Number : Positive) return String is
subtype Digit is Integer range 0..9;
function Roman (Figure : Digit; I, V, X : Character) return String is
begin
case Figure is
when 0 => return "";
when 1 => return "" & I;
when 2 => return I & I;
when 3 => return I & I & I;
when 4 => return I & V;
when 5 => return "" & V;
when 6 => return V & I;
when 7 => return V & I & I;
when 8 => return V & I & I & I;
when 9 => return I & X;
end case;
end Roman;
begin
pragma Assert (Number >= 1 and Number < 4000);
return
Roman (Number / 1000, 'M', ' ', ' ') &
Roman (Number / 100 mod 10, 'C', 'D', 'M') &
Roman (Number / 10 mod 10, 'X', 'L', 'C') &
Roman (Number mod 10, 'I', 'V', 'X');
end To_Roman;
begin
Put_Line (To_Roman (1999)); Put_Line (To_Roman (25)); Put_Line (To_Roman (944));
end Roman_Numeral_Test;</lang>
- Output:
MCMXCIX XXV CMXLIV
ALGOL 68
<lang algol68>[]CHAR roman = "MDCLXVmdclxvi"; # UPPERCASE for thousands # []CHAR adjust roman = "CCXXmmccxxii"; []INT arabic = (1000000, 500000, 100000, 50000, 10000, 5000, 1000, 500, 100, 50, 10, 5, 1); []INT adjust arabic = (100000, 100000, 10000, 10000, 1000, 1000, 100, 100, 10, 10, 1, 1, 0);
PROC arabic to roman = (INT dclxvi)STRING: (
INT in := dclxvi; # 666 #
STRING out := "";
FOR scale TO UPB roman WHILE in /= 0 DO
INT multiples = in OVER arabic[scale];
in -:= arabic[scale] * multiples;
out +:= roman[scale] * multiples;
IF in >= -adjust arabic[scale] + arabic[scale] THEN
in -:= -adjust arabic[scale] + arabic[scale];
out +:= adjust roman[scale] + roman[scale]
FI
OD;
out
);
main:(
[]INT test = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,25,30,40,50,60,69,70,
80,90,99,100,200,300,400,500,600,666,700,800,900,1000,1009,1444,1666,1945,1997,1999,
2000,2008,2500,3000,4000,4999,5000,6666,10000,50000,100000,500000,1000000,max int);
FOR key TO UPB test DO
INT val = test[key];
print((val, " - ", arabic to roman(val), new line))
OD
)</lang>
- Output:
(last example is manually wrapped)
+1 - i
+2 - ii
+3 - iii
+4 - iv
+5 - v
+6 - vi
+7 - vii
+8 - viii
+9 - ix
+10 - x
+11 - xi
+12 - xii
+13 - xiii
+14 - xiv
+15 - xv
+16 - xvi
+17 - xvii
+18 - xviii
+19 - xix
+20 - xx
+25 - xxv
+30 - xxx
+40 - xl
+50 - l
+60 - lx
+69 - lxix
+70 - lxx
+80 - lxxx
+90 - xc
+99 - xcix
+100 - c
+200 - cc
+300 - ccc
+400 - cd
+500 - d
+600 - dc
+666 - dclxvi
+700 - dcc
+800 - dccc
+900 - cm
+1000 - m
+1009 - mix
+1444 - mcdxliv
+1666 - mdclxvi
+1945 - mcmxlv
+1997 - mcmxcvii
+1999 - mcmxcix
+2000 - mm
+2008 - mmviii
+2500 - mmd
+3000 - mmm
+4000 - mV
+4999 - mVcmxcix
+5000 - V
+6666 - Vmdclxvi
+10000 - X
+50000 - L
+100000 - C
+500000 - D
+1000000 - M
+2147483647 - MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMCDLXXXmmmdcxlvii
ALGOL W
<lang algolw>BEGIN
PROCEDURE ROMAN (INTEGER VALUE NUMBER; STRING(15) RESULT CHARACTERS; INTEGER RESULT LENGTH);
COMMENT
Returns the Roman number of an integer between 1 and 3999.
"MMMDCCCLXXXVIII" (15 characters long) is the longest Roman number under 4000;
BEGIN
INTEGER PLACE, POWER;
PROCEDURE APPEND (STRING(1) VALUE C);
BEGIN CHARACTERS(LENGTH|1) := C; LENGTH := LENGTH + 1 END;
PROCEDURE I; APPEND(CASE PLACE OF ("I","X","C","M"));
PROCEDURE V; APPEND(CASE PLACE OF ("V","L","D"));
PROCEDURE X; APPEND(CASE PLACE OF ("X","C","M"));
ASSERT (NUMBER >= 1) AND (NUMBER < 4000);
CHARACTERS := " ";
LENGTH := 0;
POWER := 1000;
PLACE := 4;
WHILE PLACE > 0 DO
BEGIN
CASE NUMBER DIV POWER + 1 OF BEGIN
BEGIN END;
BEGIN I END;
BEGIN I; I END;
BEGIN I; I; I END;
BEGIN I; V END;
BEGIN V END;
BEGIN V; I END;
BEGIN V; I; I END;
BEGIN V; I; I; I END;
BEGIN I; X END
END;
NUMBER := NUMBER REM POWER;
POWER := POWER DIV 10;
PLACE := PLACE - 1
END
END ROMAN;
INTEGER I; STRING(15) S;
ROMAN(1, S, I); WRITE(S, I); ROMAN(3999, S, I); WRITE(S, I); ROMAN(3888, S, I); WRITE(S, I); ROMAN(2009, S, I); WRITE(S, I); ROMAN(405, S, I); WRITE(S, I); END.</lang>
- Output:
I 1 MMMCMXCIX 9 MMMDCCCLXXXVIII 15 MMIX 4 CDV 3
APL
<lang APL>toRoman←{
⍝ Digits and corresponding values
ds←((⊢≠⊃)⊆⊢)' M CM D CD C XC L XL X IX V IV I'
vs←1000, ,100 10 1∘.×9 5 4 1
⍝ Input ≤ 0 is invalid
⍵≤0:⎕SIGNAL 11
{ 0=d←⊃⍸vs≤⍵:⍬ ⍝ Find highest digit in number
(d⊃ds),∇⍵-d⊃vs ⍝ While one exists, add it and subtract from number
}⍵
}</lang>
- Output:
toRoman¨ 1990 2008 1666 2021 MCMXC MMVIII MDCLXVI MMXXI
AppleScript
(ES6 version)
(mapAccumL version) <lang AppleScript>------------------ ROMAN INTEGER STRINGS -----------------
-- roman :: Int -> String on roman(n)
set kvs to {["M", 1000], ["CM", 900], ["D", 500], ¬
["CD", 400], ["C", 100], ["XC", 90], ["L", 50], ¬
["XL", 40], ["X", 10], ["IX", 9], ["V", 5], ¬
["IV", 4], ["I", 1]}
script stringAddedValueDeducted
on |λ|(balance, kv)
set {k, v} to kv
set {q, r} to quotRem(balance, v)
if q > 0 then
{r, concat(replicate(q, k))}
else
{r, ""}
end if
end |λ|
end script
concat(snd(mapAccumL(stringAddedValueDeducted, n, kvs)))
end roman
TEST -------------------------
on run
map(roman, [2016, 1990, 2008, 2000, 1666])
--> {"MMXVI", "MCMXC", "MMVIII", "MM", "MDCLXVI"}
end run
GENERIC LIBRARY FUNCTIONS ---------------
-- concat :: a -> [a] | [String] -> String on concat(xs)
script append
on |λ|(a, b)
a & b
end |λ|
end script
if length of xs > 0 and ¬
class of (item 1 of xs) is string then
set unit to ""
else
set unit to {}
end if
foldl(append, unit, xs)
end concat
-- foldl :: (a -> b -> a) -> a -> [b] -> a on foldl(f, startValue, xs)
tell mReturn(f)
set v to startValue
set lng to length of xs
repeat with i from 1 to lng
set v to |λ|(v, item i of xs, i, xs)
end repeat
return v
end tell
end foldl
-- map :: (a -> b) -> [a] -> [b] on map(f, xs)
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, i, xs)
end repeat
return lst
end tell
end map
-- 'The mapAccumL function behaves like a combination of map and foldl; -- it applies a function to each element of a list, passing an -- accumulating parameter from left to right, and returning a final -- value of this accumulator together with the new list.' (see Hoogle)
-- mapAccumL :: (acc -> x -> (acc, y)) -> acc -> [x] -> (acc, [y]) on mapAccumL(f, acc, xs)
script
on |λ|(a, x)
tell mReturn(f) to set pair to |λ|(item 1 of a, x)
[item 1 of pair, (item 2 of a) & {item 2 of pair}]
end |λ|
end script
foldl(result, [acc, {}], xs)
end mapAccumL
-- Lift 2nd class handler function into 1st class script wrapper -- mReturn :: Handler -> Script on mReturn(f)
if class of f is script then
f
else
script
property |λ| : f
end script
end if
end mReturn
-- quotRem :: Integral a => a -> a -> (a, a) on quotRem(m, n)
{m div n, m mod n}
end quotRem
-- Egyptian multiplication - progressively doubling a list, appending -- stages of doubling to an accumulator where needed for binary -- assembly of a target length
-- replicate :: Int -> a -> [a] on replicate(n, a)
set out to {}
if n < 1 then return out
set dbl to {a}
repeat while (n > 1)
if (n mod 2) > 0 then set out to out & dbl
set n to (n div 2)
set dbl to (dbl & dbl)
end repeat
return out & dbl
end replicate
-- snd :: (a, b) -> b on snd(xs)
if class of xs is list and length of xs = 2 then
item 2 of xs
else
missing value
end if
end snd</lang>
- Output:
{"MMXVI", "MCMXC", "MMVIII", "MM", "MDCLXVI"}
Arturo
<lang rebol>nums: [[1000 "M"] [900 "CM"] [500 "D"] [400 "CD"] [100 "C"] [90 "XC"]
[50 "L"] [40 "XL"] [10 "X"] [9 "IX"] [5 "V"] [4 "IV"] [1 "I"])
toRoman: function [x][
ret: ""
idx: 0
initial: x
loop nums 'num [
d: num\0
l: num\1
i: 0
while [i<initial/d] [
ret: ret ++ l
i: i+1
]
initial: mod initial d ] return ret
]
loop [1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 25 30 40
50 60 69 70 80 90 99 100 200 300 400 500 600 666 700 800 900
1000 1009 1444 1666 1945 1997 1999 2000 2008 2010 2011 2500
3000 3999] 'n
-> print [n "->" toRoman n]</lang>
- Output:
1 -> I 2 -> II 3 -> III 4 -> IV 5 -> V 6 -> VI 7 -> VII 8 -> VIII 9 -> IX 10 -> X 11 -> XI 12 -> XII 13 -> XIII 14 -> XIV 15 -> XV 16 -> XVI 17 -> XVII 18 -> XVIII 19 -> XIX 20 -> XX 25 -> XXV 30 -> XXX 40 -> XL 50 -> L 60 -> LX 69 -> LXIX 70 -> LXX 80 -> LXXX 90 -> XC 99 -> XCIX 100 -> C 200 -> CC 300 -> CCC 400 -> CD 500 -> D 600 -> DC 666 -> DCLXVI 700 -> DCC 800 -> DCCC 900 -> CM 1000 -> M 1009 -> MIX 1444 -> MCDXLIV 1666 -> MDCLXVI 1945 -> MCMXLV 1997 -> MCMXCVII 1999 -> MCMXCIX 2000 -> MM 2008 -> MMVIII 2010 -> MMX 2011 -> MMXI 2500 -> MMD 3000 -> MMM 3999 -> MMMCMXCIX
AutoHotkey
<lang AutoHotkey>MsgBox % stor(444)
stor(value) {
romans = M,CM,D,CD,C,XC,L,XL,X,IX,V,IV,I
M := 1000
CM := 900
D := 500
CD := 400
C := 100
XC := 90
L := 50
XL := 40
X := 10
IX := 9
V := 5
IV := 4
I := 1
Loop, Parse, romans, `,
{
While, value >= %A_LoopField%
{
result .= A_LoopField
value := value - (%A_LoopField%)
}
}
Return result . "O"
}</lang>
Autolisp
<lang Autolisp> (defun c:roman() (romanNumber (getint "\n Enter number > ")) (defun romanNumber (n / uni dec hun tho nstr strlist nlist rom)
(if (and (> n 0) (<= n 3999))
(progn
(setq
UNI (list "" "I" "II" "III" "IV" "V" "VI" "VII" "VIII" "IX")
DEC (list "" "X" "XX" "XXX" "XL" "L" "LX" "LXX" "LXXX" "XC")
HUN (list "" "C" "CC" "CCC" "CD" "D" "DC" "DCC" "DCCC" "CM")
THO (list "" "M" "MM" "MMM")
nstr (itoa n)
)
(while (> (strlen nstr) 0) (setq strlist (append strlist (list (substr nstr 1 1))) nstr (substr nstr 2 (strlen nstr))))
(setq nlist (mapcar 'atoi strlist))
(cond
((> n 999)(setq rom(strcat(nth (car nlist) THO)(nth (cadr nlist) HUN)(nth (caddr nlist) DEC) (nth (last nlist)UNI ))))
((and (> n 99)(<= n 999))(setq rom(strcat (nth (car nlist) HUN)(nth (cadr nlist) DEC) (nth (last nlist)UNI ))))
((and (> n 9)(<= n 99))(setq rom(strcat (nth (car nlist) DEC) (nth (last nlist)UNI ))))
((<= n 9)(setq rom(nth (last nlist)UNI)))
)
)
(princ "\nNumber out of range!")
)
rom ) </lang>
- Output:
1577 "MDLXXVII" 3999 "MMMCMXCIX" 888 "DCCCLXXXVIII" 159 "CLIX"
AWK
<lang AWK>
- syntax: GAWK -f ROMAN_NUMERALS_ENCODE.AWK
BEGIN {
leng = split("1990 2008 1666",arr," ")
for (i=1; i<=leng; i++) {
n = arr[i]
printf("%s = %s\n",n,dec2roman(n))
}
exit(0)
} function dec2roman(number, v,w,x,y,roman1,roman10,roman100,roman1000) {
number = int(number) # force to integer
if (number < 1 || number > 3999) { # number is too small | big
return
}
split("I II III IV V VI VII VIII IX",roman1," ") # 1 2 ... 9
split("X XX XXX XL L LX LXX LXXX XC",roman10," ") # 10 20 ... 90
split("C CC CCC CD D DC DCC DCCC CM",roman100," ") # 100 200 ... 900
split("M MM MMM",roman1000," ") # 1000 2000 3000
v = (number - (number % 1000)) / 1000
number = number % 1000
w = (number - (number % 100)) / 100
number = number % 100
x = (number - (number % 10)) / 10
y = number % 10
return(roman1000[v] roman100[w] roman10[x] roman1[y])
} </lang>
- Output:
1990 = MCMXC 2008 = MMVIII 1666 = MDCLXVI
BASIC
Applesoft BASIC
<lang gwbasic> 1 N = 1990: GOSUB 5: PRINT N" = "V$
2 N = 2008: GOSUB 5: PRINT N" = "V$
3 N = 1666: GOSUB 5: PRINT N" = "V$;
4 END
5 V = N:V$ = "": FOR I = 0 TO 12: FOR L = 1 TO 0 STEP 0:A = VAL ( MID$ ("1E3900500400100+90+50+40+10+09+05+04+01",I * 3 + 1,3))
6 L = (V - A) > = 0:V$ = V$ + MID$ ("M.CMD.CDC.XCL.XLX.IXV.IVI",I * 2 + 1,(I - INT (I / 2) * 2 + 1) * L):V = V - A * L: NEXT L,I
7 RETURN</lang>
ASIC
<lang basic> REM Roman numerals/Encode DIM Weights(12) DIM Symbols$(12) DATA 1000, "M", 900, "CM", 500, "D", 400, "CD", 100, "C", 90, "XC", 50, "L" DATA 40, "XL", 10, "X", 9, "IX", 5, "V", 4, "IV", 1, "I" REM 3888 or MMMDCCCLXXXVIII (15 chars) is the longest string properly encoded REM with these symbols. FOR J = 0 TO 12
READ Weights(J) READ Symbols$(J)
NEXT J
AValue = 1990 GOSUB ToRoman: PRINT Roman$ REM MCMXC AValue = 2022 GOSUB ToRoman: PRINT Roman$ REM MMXXII AValue = 3888 GOSUB ToRoman: PRINT Roman$ REM MMMDCCCLXXXVIII END
ToRoman: REM Result: Roman$ Roman$ = "" I = 0 Loop:
IF (I > 12 THEN ExitToRoman: IF AValue <= 0 THEN ExitToRoman: WHILE AValue >= Weights(I) Roman$ = Roman$ + Symbols$(I) AValue = AValue - Weights(I) WEND I = I + 1 GOTO Loop:
ExitToRoman: RETURN </lang>
Commodore BASIC
C-128 version: <lang basic>100 DIM RN$(12),NV(12) 110 FOR I=0 TO 12 120 : READ RN$(I), NV(I) 130 NEXT I 140 DATA M,1000, CM,900, D,500, CD,400 150 DATA C, 100, XC, 90, L, 50, XL, 40 160 DATA X, 10, IX, 9, V, 5, IV, 4 170 DATA I, 1 180 PRINT CHR$(19);CHR$(19);CHR$(147);CHR$(18); 190 PRINT "***** ROMAN NUMERAL ENCODER *****";CHR$(27);"T" 200 DO 210 : PRINT "ENTER NUMBER (0 TO QUIT):"; 220 : OPEN 1,0:INPUT#1,AN$:CLOSE 1:PRINT 230 : AN=VAL(AN$):IF AN=0 THEN EXIT 240 : RN$="" 250 : DO WHILE AN > 0 260 : FOR I=0 TO 12 270 : IF AN >= NV(I) THEN BEGIN 280 : RN$ = RN$+ RN$(I) 290 : AN = AN - NV(I) 300 : GOTO 330 310 : BEND 320 : NEXT I 330 : LOOP 340 : PRINT RN$;CHR$(13) 350 LOOP</lang>
C-16/116/Plus-4 version (BASIC 3.5 has DO/LOOP but not BEGIN/BEND) <lang basic>100 DIM RN$(12),NV(12) 110 FOR I=0 TO 12 120 : READ RN$(I), NV(I) 130 NEXT I 140 DATA M,1000, CM,900, D,500, CD,400 150 DATA C, 100, XC, 90, L, 50, XL, 40 160 DATA X, 10, IX, 9, V, 5, IV, 4 170 DATA I, 1 180 PRINT CHR$(19);CHR$(19);CHR$(147);CHR$(18); 190 PRINT "***** ROMAN NUMERAL ENCODER *****";CHR$(27);"T" 200 DO 210 : PRINT "ENTER NUMBER (0 TO QUIT):"; 220 : OPEN 1,0:INPUT#1,AN$:CLOSE 1:PRINT 230 : AN=VAL(AN$):IF AN=0 THEN EXIT 240 : RN$="" 250 : DO WHILE AN > 0 260 : FOR I=0 TO 12 270 : IF AN < NV(I) THEN 320 280 : RN$ = RN$+ RN$(I) 290 : AN = AN - NV(I) 300 : I = 12 320 : NEXT I 330 : LOOP 340 : PRINT RN$;CHR$(13) 350 LOOP</lang>
This version works on any Commodore, though the title banner should be adjusted to match the color and screen width of the particular machine. <lang basic>100 DIM RN$(12),NV(12) 110 FOR I=0 TO 12 120 : READ RN$(I), NV(I) 130 NEXT I 140 DATA M,1000, CM,900, D,500, CD,400 150 DATA C, 100, XC, 90, L, 50, XL, 40 160 DATA X, 10, IX, 9, V, 5, IV, 4 170 DATA I, 1 180 PRINT CHR$(19);CHR$(19);CHR$(147);CHR$(18); 190 PRINT "***** ROMAN NUMERAL ENCODER *****"; 200 REM BEGIN MAIN LOOP 210 : PRINT "NUMBER (0 TO QUIT):"; 220 : OPEN 1,0:INPUT#1,AN$:CLOSE 1:PRINT 230 : AN=VAL(AN$):IF AN=0 THEN END 240 : RN$="" 250 : IF AN <= 0 THEN 340 260 : FOR I=0 TO 12 270 : IF AN < NV(I) THEN 320 280 : RN$ = RN$+ RN$(I) 290 : AN = AN - NV(I) 300 : I = 12 320 : NEXT I 330 : GOTO 250 340 : PRINT RN$;CHR$(13) 350 GOTO 210 </lang>
The output is the same for all the above versions:
- Output:
***** ROMAN NUMERAL ENCODER ***** ENTER NUMBER (0 TO QUIT):2009 MMIX ENTER NUMBER (0 TO QUIT):1666 MDCLXVI ENTER NUMBER (0 TO QUIT):3888 MMMDCCCLXXXVIII ENTER NUMBER (0 TO QUIT):0 READY.
FreeBASIC
<lang freebasic> DIM SHARED arabic(0 TO 12) AS Integer => {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 } DIM SHARED roman(0 TO 12) AS String*2 => {"M", "CM", "D","CD", "C","XC","L","XL","X","IX","V","IV","I"}
FUNCTION toRoman(value AS Integer) AS String
DIM i AS Integer
DIM result AS String
FOR i = 0 TO 12
DO WHILE value >= arabic(i)
result = result + roman(i) value = value - arabic(i) LOOP
NEXT i toRoman = result
END FUNCTION
'Testing PRINT "2009 = "; toRoman(2009) PRINT "1666 = "; toRoman(1666) PRINT "3888 = "; toRoman(3888) </lang>
- Output:
2009 = MMIX 1666 = MDCLXVI 3888 = MMMDCCCLXXXVIII
IS-BASIC
<lang IS-BASIC>100 PROGRAM "Roman.bas" 110 DO 120 PRINT :INPUT PROMPT "Enter an arabic number: ":N 130 IF N<1 THEN EXIT DO 140 PRINT TOROMAN$(N) 150 LOOP 160 DEF TOROMAN$(X) 170 IF X>3999 THEN 180 LET TOROMAN$="Too big." 190 EXIT DEF 200 END IF 210 RESTORE 220 LET SUM$="" 230 FOR I=1 TO 13 240 READ ARABIC,ROMAN$ 250 DO WHILE X>=ARABIC 260 LET SUM$=SUM$&ROMAN$ 270 LET X=X-ARABIC 280 LOOP 290 NEXT 300 LET TOROMAN$=SUM$ 310 END DEF 320 DATA 1000,"M",900,"CM",500,"D",400,"CD",100,"C",90,"XC" 330 DATA 50,"L",40,"XL",10,"X",9,"IX",5,"V",4,"IV",1,"I"</lang>
Nascom BASIC
<lang basic> 10 REM Roman numerals/Encode 20 DIM WEIGHTS(12),SYMBOLS$(12) 30 FOR I=0 TO 12 40 READ WEIGHTS(I),SYMBOLS$(I) 50 NEXT I 60 DATA 1000,M,900,CM,500,D,400,CD,100,C,90,XC 70 DATA 50,L,40,XL,10,X,9,IX,5,V,4,IV,1,I 80 REM ** 3888 or MMMDCCCLXXXVIII (15 chars) is 90 REM the longest string properly encoded 100 REM with these symbols. 110 V=1990:GOSUB 500 120 PRINT ROMAN$:REM MCMXC 130 V=2022:GOSUB 500 140 PRINT ROMAN$:REM MMXXII 150 V=3888:GOSUB 500 160 PRINT ROMAN$:REM MMMDCCCLXXXVIII 170 END 490 REM ** Encode to roman 500 ROMAN$="" 510 I=0 520 IF I>12 OR V<=0 THEN RETURN 530 IF V<WEIGHTS(I) THEN 570 540 ROMAN$=ROMAN$+SYMBOLS$(I) 550 V=V-WEIGHTS(I) 560 GOTO 530 570 I=I+1 580 GOTO 520 590 RETURN </lang>
- Output:
MCMXC MMXXII MMMDCCCLXXXVIII
ZX Spectrum Basic
<lang zxbasic> 10 DATA 1000,"M",900,"CM"
20 DATA 500,"D",400,"CD" 30 DATA 100,"C",90,"XC" 40 DATA 50,"L",40,"XL" 50 DATA 10,"X",9,"IX" 60 DATA 5,"V",4,"IV",1,"I" 70 INPUT "Enter an arabic number: ";V 80 LET VALUE=V 90 LET V$=""
100 FOR I=0 TO 12 110 READ A,R$ 120 IF V<A THEN GO TO 160 130 LET V$=V$+R$ 140 LET V=V-A 150 GO TO 120 160 NEXT I 170 PRINT VALUE;"=";V$</lang>
BaCon
<lang bacon>OPTION BASE 1
GLOBAL roman$[] = { "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I" } GLOBAL number[] = { 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 }
FUNCTION toroman$(value)
LOCAL result$
DOTIMES UBOUND(number)
WHILE value >= number[_]
result$ = result$ & roman$[_]
DECR value, number[_]
WEND
DONE
RETURN result$
ENDFUNC
PRINT toroman$(1990) PRINT toroman$(2008) PRINT toroman$(1666) </lang>
- Output:
MCMXC MMVIII MDCLXVI
BASIC256
<lang basic256> print 1666+" = "+convert$(1666) print 2008+" = "+convert$(2008) print 1001+" = "+convert$(1001) print 1999+" = "+convert$(1999)
function convert$(value) convert$="" arabic = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 } roman$ = {"M", "CM", "D","CD", "C","XC","L","XL","X","IX","V","IV","I"}
for i = 0 to 12
while value >= arabic[i]
convert$ += roman$[i] value = value - arabic[i] end while
next i
end function </lang>
- Output:
1666 = MDCLXVI 2008 = MMVIII 1001 = MI 1999 = MCMXCIX
Batch File
<lang dos>@echo off setlocal enabledelayedexpansion
set cnt=0&for %%A in (1000,900,500,400,100,90,50,40,10,9,5,4,1) do (set arab!cnt!=%%A&set /a cnt+=1) set cnt=0&for %%R in (M,CM,D,CD,C,XC,L,XL,X,IX,V,IV,I) do (set rom!cnt!=%%R&set /a cnt+=1)
- Testing
call :toRoman 2009 echo 2009 = !result! call :toRoman 1666 echo 1666 = !result! call :toRoman 3888 echo 3888 = !result! pause>nul exit/b 0
- The "function"...
- toRoman
set value=%1 set result=
for /l %%i in (0,1,12) do ( set a=%%i call :add_val ) goto :EOF
- add_val
if !value! lss !arab%a%! goto :EOF set result=!result!!rom%a%! set /a value-=!arab%a%! goto add_val</lang>
- Output:
2009 = MMIX 1666 = MDCLXVI 3888 = MMMDCCCLXXXVIII
BBC BASIC
<lang bbcbasic> PRINT ;1999, FNroman(1999)
PRINT ;2012, FNroman(2012)
PRINT ;1666, FNroman(1666)
PRINT ;3888, FNroman(3888)
END
DEF FNroman(n%)
LOCAL i%, r$, arabic%(), roman$()
DIM arabic%(12), roman$(12)
arabic%() = 1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900,1000
roman$() = "I","IV", "V","IX", "X","XL", "L","XC", "C","CD", "D","CM", "M"
FOR i% = 12 TO 0 STEP -1
WHILE n% >= arabic%(i%)
r$ += roman$(i%)
n% -= arabic%(i%)
ENDWHILE
NEXT
= r$</lang>
- Output:
1999 MCMXCIX 2012 MMXII 1666 MDCLXVI 3888 MMMDCCCLXXXVIII
BCPL
<lang bcpl>get "libhdr"
let toroman(n, v) = valof $( let extract(n, val, rmn, v) = valof
$( while n >= val
$( n := n - val;
for i=1 to rmn%0 do v%(v%0+i) := rmn%i
v%0 := v%0 + rmn%0
$)
resultis n
$)
v%0 := 0
n := extract(n, 1000, "M", v)
n := extract(n, 900, "CM", v)
n := extract(n, 500, "D", v)
n := extract(n, 400, "CD", v)
n := extract(n, 100, "C", v)
n := extract(n, 90, "XC", v)
n := extract(n, 50, "L", v)
n := extract(n, 40, "XL", v)
n := extract(n, 10, "X", v)
n := extract(n, 9, "IX", v)
n := extract(n, 5, "V", v)
n := extract(n, 4, "IV", v)
n := extract(n, 1, "I", v)
resultis v
$)
let show(n) be $( let v = vec 50
writef("%I4 = %S*N", n, toroman(n, v))
$)
let start() be $( show(1666)
show(2008) show(1001) show(1999) show(3888) show(2021)
$)</lang>
- Output:
1666 = MDCLXVI 2008 = MMVIII 1001 = MI 1999 = MCMXCIX 3888 = MMMDCCCLXXXVIII 2021 = MMXXI
Befunge
Reads the number to convert from standard input. No range validation is performed.
<lang befunge>&>0\0>00p:#v_$ >:#,_ $ @ 4-v >5+#:/#<\55+%:5/\5%: vv_$9+00g+5g\00g8+>5g\00 g>\20p>:10p00g \#v _20gv > 2+ v^-1g01\g5+8<^ +9 _
IVXLCDM</lang>
- Output:
1666 MDCLXVI
BQN
<lang BQN>⟨ToRoman⇐R⟩ ← {
ds ← 1↓¨(¯1+`⊏⊸=)⊸⊔" I IV V IX X XL L XC C CD D CM M"
vs ← 1e3∾˜ ⥊1‿4‿5‿9×⌜˜10⋆↕3
R ⇐ {
𝕨𝕊0: "";
(⊑⟜ds∾·𝕊𝕩-⊑⟜vs) 1-˜⊑vs⍋𝕩
}
}</lang>
- Example use:
<lang> ToRoman¨ 1990‿2008‿1666‿2021 ⟨ "MCMXC" "MMVIII" "MDCLXVI" "MMXXI" ⟩</lang>
Bracmat
<lang bracmat>( ( encode
= indian roman cifr tenfoldroman letter tenfold
. !arg:#?indian
& :?roman
& whl
' ( @(!indian:#%?cifr ?indian)
& :?tenfoldroman
& whl
' ( !roman:%?letter ?roman
& !tenfoldroman
( (I.X)
(V.L)
(X.C)
(L.D)
(C.M)
: ? (!letter.?tenfold) ?
& !tenfold
| "*"
)
: ?tenfoldroman
)
& !tenfoldroman:?roman
& ( !cifr:9&!roman I X:?roman
| !cifr:~<4
& !roman
(!cifr:4&I|)
V
: ?roman
& !cifr+-5:?cifr
& ~
| whl
' ( !cifr+-1:~<0:?cifr
& !roman I:?roman
)
)
)
& ( !roman:? "*" ?&~`
| str$!roman
)
)
& 1990 2008 1666 3888 3999 4000:?NS & whl
' ( !NS:%?N ?NS
& out
$ ( encode$!N:?K&!N !K
| str$("Can't convert " !N " to Roman numeral")
)
)
);</lang>
- Output:
1990 MCMXC 2008 MMVIII 1666 MDCLXVI 3888 MMMDCCCLXXXVIII 3999 MMMCMXCIX Can't convert 4000 to Roman numeral
C
Naive solution
This solution is a smart but does not return the number written as a string. <lang c>#include <stdio.h>
int main() {
int arabic[] = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
// There is a bug: "XL\0" is translated into sequence 58 4C 00 00, i.e. it is 4-bytes long...
// Should be "XL" without \0 etc.
//
char roman[13][3] = {"M\0", "CM\0", "D\0", "CD\0", "C\0", "XC\0", "L\0", "XL\0", "X\0", "IX\0", "V\0", "IV\0", "I\0"};
int N;
printf("Enter arabic number:\n");
scanf("%d", &N);
printf("\nRoman number:\n");
for (int i = 0; i < 13; i++) {
while (N >= arabic[i]) {
printf("%s", roman[i]);
N -= arabic[i];
}
}
return 0;
} </lang>
- Output:
Enter arabic number: 215 Roman number: CCXV
Not thread-safe
<lang C>#define _CRT_SECURE_NO_WARNINGS
- include <stdio.h>
- include <string.h>
int RomanNumerals_parseInt(const char* string) {
int value;
return scanf("%u", &value) == 1 && value > 0 ? value : 0;
}
const char* RomanNumerals_toString(int value) {
- define ROMAN_NUMERALS_MAX_OUTPUT_STRING_SIZE 64
static buffer[ROMAN_NUMERALS_MAX_OUTPUT_STRING_SIZE];
const static int maxValue = 5000; const static int minValue = 1;
const static struct Digit {
char string[4]; // It's better to use 4 than 3 (aligment).
int value;
} digits[] = {
{"M", 1000}, {"CM", 900}, {"D", 500 }, {"CD", 400 },
{"C", 100 }, {"XC", 90 }, {"L", 50 }, {"XL", 40},
{"X", 10}, {"IX", 9}, {"V", 5}, {"IV", 4}, {"I", 1 },
{"?", 0}
};
*buffer = '\0'; // faster than memset(buffer, 0, sizeof(buffer));
if (minValue <= value && value <= maxValue)
{
struct Digit* digit = &digits[0];
while (digit->value)
{
while (value >= digit->value)
{
value -= digit->value;
// It is not necessary - total length would not be exceeded...
// if (strlen(buffer) + strlen(digit->string) < sizeof(buffer))
strcat(buffer, digit->string);
}
digit++;
}
}
return buffer;
}
int main(int argc, char* argv[])
{
if (argc < 2)
{
// Blanks are needed for a consistient blackground on some systems.
// BTW, puts append an extra newline at the end.
//
puts("Write given numbers as Roman numerals. \n"
" \n"
"Usage: \n"
" roman n1 n2 n3 ... \n"
" \n"
"where n1 n2 n3 etc. are Arabic numerals\n");
int numbers[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1498, 2022 };
for (int i = 0; i < sizeof(numbers) / sizeof(int); i++)
{
printf("%4d = %s\n",
numbers[i], RomanNumerals_toString(numbers[i]));
}
}
else
{
for (int i = 1; i < argc; i++)
{
int number = RomanNumerals_parseInt(argv[i]);
if (number)
{
puts(RomanNumerals_toString(number));
}
else
{
puts("???");
}
}
}
return 0;
}</lang>
- Output:
Write given numbers as Roman numerals.
Usage:
roman n1 n2 n3 ...
where n1 n2 n3 etc. are Arabic numerals
1 = I
2 = II
3 = III
4 = IV
5 = V
6 = VI
7 = VII
8 = VIII
9 = IX
10 = X
1498 = MCDXCVIII
2022 = MMXXII
C#
<lang csharp>using System; class Program {
static uint[] nums = { 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 };
static string[] rum = { "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I" };
static string ToRoman(uint number)
{
string value = "";
for (int i = 0; i < nums.Length && number != 0; i++)
{
while (number >= nums[i])
{
number -= nums[i];
value += rum[i];
}
}
return value;
}
static void Main()
{
for (uint number = 1; number <= 1 << 10; number *= 2)
{
Console.WriteLine("{0} = {1}", number, ToRoman(number));
}
}
}</lang>
One-liner Mono REPL <lang csharp> Func<int, string> toRoman = (number) =>
new Dictionary<int, string>
{
{1000, "M"},
{900, "CM"},
{500, "D"},
{400, "CD"},
{100, "C"},
{90, "XC"},
{50, "L"},
{40, "XL"},
{10, "X"},
{9, "IX"},
{5, "V"},
{4, "IV"},
{1, "I"}
}.Aggregate(new string('I', number), (m, _) => m.Replace(new string('I', _.Key), _.Value));
</lang>
- Output:
1 = I 2 = II 4 = IV 8 = VIII 16 = XVI 32 = XXXII 64 = LXIV 128 = CXXVIII 256 = CCLVI 512 = DXII 1024 = MXXIV
C++
C++ 98
<lang cpp>#include <iostream>
- include <string>
std::string to_roman(int value) {
struct romandata_t { int value; char const* numeral; };
static romandata_t const romandata[] =
{ 1000, "M",
900, "CM",
500, "D",
400, "CD",
100, "C",
90, "XC",
50, "L",
40, "XL",
10, "X",
9, "IX",
5, "V",
4, "IV",
1, "I",
0, NULL }; // end marker
std::string result;
for (romandata_t const* current = romandata; current->value > 0; ++current)
{
while (value >= current->value)
{
result += current->numeral;
value -= current->value;
}
}
return result;
}
int main() {
for (int i = 1; i <= 4000; ++i)
{
std::cout << to_roman(i) << std::endl;
}
}</lang>
C++ 11
<lang cpp>#include <iostream>
- include <string>
std::string to_roman(int x) {
if (x <= 0)
return "Negative or zero!";
auto roman_digit = [](char one, char five, char ten, int x) {
if (x <= 3)
return std::string().assign(x, one);
if (x <= 5)
return std::string().assign(5 - x, one) + five;
if (x <= 8)
return five + std::string().assign(x - 5, one);
return std::string().assign(10 - x, one) + ten;
};
if (x >= 1000)
return x - 1000 > 0 ? "M" + to_roman(x - 1000) : "M";
if (x >= 100) {
auto s = roman_digit('C', 'D', 'M', x / 100);
return x % 100 > 0 ? s + to_roman(x % 100) : s;
}
if (x >= 10) {
auto s = roman_digit('X', 'L', 'C', x / 10);
return x % 10 > 0 ? s + to_roman(x % 10) : s;
}
return roman_digit('I', 'V', 'X', x);
}
int main() {
for (int i = 0; i < 2018; i++)
std::cout << i << " --> " << to_roman(i) << std::endl;
}</lang>
Ceylon
<lang ceylon>shared void run() {
class Numeral(shared Character char, shared Integer int) {}
value tiers = [ [Numeral('I', 1), Numeral('V', 5), Numeral('X', 10)], [Numeral('X', 10), Numeral('L', 50), Numeral('C', 100)], [Numeral('C', 100), Numeral('D', 500), Numeral('M', 1k)] ];
String toRoman(Integer hindu, Integer tierIndex = 2) {
assert (exists tier = tiers[tierIndex]);
" Finds if it's a two character numeral like iv, ix, xl, xc, cd and cm." function findTwoCharacterNumeral() => if (exists bigNum = tier.rest.find((numeral) => numeral.int - tier.first.int <= hindu < numeral.int)) then [tier.first, bigNum] else null;
if (hindu <= 0) { // if it's zero then we are done! return ""; } else if (exists [smallNum, bigNum] = findTwoCharacterNumeral()) { value twoCharSymbol = "``smallNum.char````bigNum.char``"; value twoCharValue = bigNum.int - smallNum.int; return "``twoCharSymbol````toRoman(hindu - twoCharValue, tierIndex)``"; } else if (exists num = tier.reversed.find((Numeral elem) => hindu >= elem.int)) { return "``num.char````toRoman(hindu - num.int, tierIndex)``"; } else { // nothing was found so move to the next smaller tier! return toRoman(hindu, tierIndex - 1); } }
assert (toRoman(1) == "I"); assert (toRoman(2) == "II"); assert (toRoman(4) == "IV"); assert (toRoman(1666) == "MDCLXVI"); assert (toRoman(1990) == "MCMXC"); assert (toRoman(2008) == "MMVIII"); }</lang>
Clojure
The easiest way is to use the built-in cl-format function <lang Clojure>(def arabic->roman
(partial clojure.pprint/cl-format nil "~@R"))
(arabic->roman 147)
- "CXXIII"
(arabic->roman 99)
- "XCIX"</lang>Alternatively
- <lang Clojure>(def roman-map
(sorted-map 1 "I", 4 "IV", 5 "V", 9 "IX", 10 "X", 40 "XL", 50 "L", 90 "XC", 100 "C", 400 "CD", 500 "D", 900 "CM" 1000 "M"))
(defn int->roman [n]
{:pre (integer? n)}
(loop [res (StringBuilder.), n n]
(if-let [v (roman-map n)]
(str (.append res v))
(let [[k v] (->> roman-map keys (filter #(> n %)) last (find roman-map))]
(recur (.append res v) (- n k))))))
(int->roman 1999)
- "MCMXCIX"</lang>
An alternate implementation:
<lang Clojure> (defn a2r [a]
(let [rv '(1000 500 100 50 10 5 1)
rm (zipmap rv "MDCLXVI")
dv (->> rv (take-nth 2) next #(interleave % %))]
(loop [a a rv rv dv dv r nil]
(if (<= a 0)
r
(let [v (first rv)
d (or (first dv) 0)
l (- v d)]
(cond
(= a v) (str r (rm v))
(= a l) (str r (rm d) (rm v))
(and (> a v) (> a l)) (recur (- a v) rv dv (str r (rm v)))
(and (< a v) (< a l)) (recur a (rest rv) (rest dv) r)
:else (recur (- a l) (rest rv) (rest dv) (str r (rm d) (rm v)))))))))
</lang>
Usage:
<lang Clojure> (a2r 1666) "MDCLXVI"
(map a2r [1000 1 389 45]) ("M" "I" "CCCLXXXIX" "XLV") </lang>
An alternate implementation:
<lang Clojure> (def roman-map
(sorted-map-by >
1 "I", 4 "IV", 5 "V", 9 "IX",
10 "X", 40 "XL", 50 "L", 90 "XC",
100 "C", 400 "CD", 500 "D", 900 "CM"
1000 "M"))
(defn a2r
([r]
(reduce str (a2r r (keys roman-map))))
([r n]
(when-not (empty? n)
(let [e (first n)
v (- r e)
roman (roman-map e)]
(cond
(< v 0) (a2r r (rest n))
(= v 0) (cons roman [])
(>= v e) (cons roman (a2r v n))
(< v e) (cons roman (a2r v (rest n))))))))
</lang>
Usage:
<lang Clojure> (a2r 1666) "MDCLXVI"
(map a2r [1000 1 389 45]) ("M" "I" "CCCLXXXIX" "XLV") </lang>
CLU
<lang clu>roman = cluster is encode
rep = null
dmap = struct[v: int, s: string]
darr = array[dmap]
own chunks: darr := darr$
[dmap${v: 1000, s: "M"},
dmap${v: 900, s: "CM"},
dmap${v: 500, s: "D"},
dmap${v: 400, s: "CD"},
dmap${v: 100, s: "C"},
dmap${v: 90, s: "XC"},
dmap${v: 50, s: "L"},
dmap${v: 40, s: "XL"},
dmap${v: 10, s: "X"},
dmap${v: 9, s: "IX"},
dmap${v: 5, s: "V"},
dmap${v: 4, s: "IV"},
dmap${v: 1, s: "I"}]
largest_chunk = proc (i: int) returns (int, string)
for chunk: dmap in darr$elements(chunks) do
if chunk.v <= i then return (chunk.v, chunk.s) end
end
return (0, "")
end largest_chunk
encode = proc (i: int) returns (string)
result: string := ""
while i > 0 do
val: int chunk: string
val, chunk := largest_chunk(i)
result := result || chunk
i := i - val
end
return (result)
end encode
end roman
start_up = proc ()
po: stream := stream$primary_output()
tests: array[int] := array[int]$[1666, 2008, 1001, 1999, 3888, 2021]
for test: int in array[int]$elements(tests) do
stream$putl(po, int$unparse(test) || " = " || roman$encode(test))
end
end start_up</lang>
- Output:
1666 = MDCLXVI 2008 = MMVIII 1001 = MI 1999 = MCMXCIX 3888 = MMMDCCCLXXXVIII 2021 = MMXXI
COBOL
<lang COBOL> IDENTIFICATION DIVISION. PROGRAM-ID. TOROMAN. DATA DIVISION. working-storage section.
01 ws-number pic 9(4) value 0.
01 ws-save-number pic 9(4).
01 ws-tbl-def.
03 filler pic x(7) value '1000M '.
03 filler pic x(7) value '0900CM '.
03 filler pic x(7) value '0500D '.
03 filler pic x(7) value '0400CD '.
03 filler pic x(7) value '0100C '.
03 filler pic x(7) value '0090XC '.
03 filler pic x(7) value '0050L '.
03 filler pic x(7) value '0040XL '.
03 filler pic x(7) value '0010X '.
03 filler pic x(7) value '0009IX '.
03 filler pic x(7) value '0005V '.
03 filler pic x(7) value '0004IV '.
03 filler pic x(7) value '0001I '.
01 filler redefines ws-tbl-def.
03 filler occurs 13 times indexed by rx.
05 ws-tbl-divisor pic 9(4).
05 ws-tbl-roman-ch pic x(1) occurs 3 times indexed by cx.
01 ocx pic 99.
01 ws-roman.
03 ws-roman-ch pic x(1) occurs 16 times.
PROCEDURE DIVISION.
accept ws-number
perform
until ws-number = 0
move ws-number to ws-save-number
if ws-number > 0 and ws-number < 4000
initialize ws-roman
move 0 to ocx
perform varying rx from 1 by +1
until ws-number = 0
perform until ws-number < ws-tbl-divisor (rx)
perform varying cx from 1 by +1
until ws-tbl-roman-ch (rx, cx) = spaces
compute ocx = ocx + 1
move ws-tbl-roman-ch (rx, cx) to ws-roman-ch (ocx)
end-perform
compute ws-number = ws-number - ws-tbl-divisor (rx)
end-perform
end-perform
display 'inp=' ws-save-number ' roman=' ws-roman
else
display 'inp=' ws-save-number ' invalid'
end-if
accept ws-number
end-perform
.
</lang>
- Output:
(input was supplied via STDIN)
inp=0111 roman=CXI inp=2234 roman=MMCCXXXIV inp=0501 roman=DI inp=0010 roman=X inp=0040 roman=XL inp=0050 roman=L inp=0066 roman=LXVI inp=0666 roman=DCLXVI inp=5666 invalid inp=3333 roman=MMMCCCXXXIII inp=3888 roman=MMMDCCCLXXXVIII inp=3999 roman=MMMCMXCIX inp=3345 roman=MMMCCCXLV
CoffeeScript
<lang coffeescript> decimal_to_roman = (n) ->
# This should work for any positive integer, although it
# gets a bit preposterous for large numbers.
if n >= 4000
thousands = decimal_to_roman n / 1000
ones = decimal_to_roman n % 1000
return "M(#{thousands})#{ones}"
s =
translate_each = (min, roman) ->
while n >= min
n -= min
s += roman
translate_each 1000, "M"
translate_each 900, "CM"
translate_each 500, "D"
translate_each 400, "CD"
translate_each 100, "C"
translate_each 90, "XC"
translate_each 50, "L"
translate_each 40, "XL"
translate_each 10, "X"
translate_each 9, "IX"
translate_each 5, "V"
translate_each 4, "IV"
translate_each 1, "I"
s
tests =
IV: 4 XLII: 42 MCMXC: 1990 MMVIII: 2008 MDCLXVI: 1666 'M(IV)': 4000 'M(VI)IX': 6009 'M(M(CXXIII)CDLVI)DCCLXXXIX': 123456789 'M(MMMV)I': 3005001
for expected, decimal of tests
roman = decimal_to_roman(decimal)
if roman == expected
console.log "#{decimal} = #{roman}"
else
console.log "error for #{decimal}: #{roman} is wrong"
</lang>
Common Lisp
<lang lisp>(defun roman-numeral (n)
(format nil "~@R" n))</lang>
Cowgol
<lang cowgol>include "cowgol.coh"; include "argv.coh";
- Encode the given number as a Roman numeral
sub decimalToRoman(num: uint16, buf: [uint8]): (rslt: [uint8]) is
# return the start of the buffer for easy printing
rslt := buf;
# Add string to buffer
sub Add(str: [uint8]) is
while [str] != 0 loop
[buf] := [str];
buf := @next buf;
str := @next str;
end loop;
end sub;
# Table of Roman numerals
record Roman is
value: uint16;
string: [uint8];
end record;
var numerals: Roman[] := {
{1000, "M"}, {900, "CM"}, {500, "D"}, {400, "CD"},
{100, "C"}, {90, "XC"}, {50, "L"}, {40, "XL"},
{10, "X"}, {9, "IX"}, {5, "V"}, {4, "IV"},
{1, "I"}
};
var curNum := &numerals as [Roman];
while num != 0 loop
while num >= curNum.value loop
Add(curNum.string);
num := num - curNum.value;
end loop;
curNum := @next curNum;
end loop;
[buf] := 0; # terminate the string
end sub;
- Read numbers from the command line and print the corresponding Roman numerals
ArgvInit(); var buffer: uint8[100]; loop
var argmt := ArgvNext();
if argmt == (0 as [uint8]) then
break;
end if;
var dummy: [uint8];
var number: int32;
(number, dummy) := AToI(argmt);
print(decimalToRoman(number as uint16, &buffer as [uint8]));
print_nl();
end loop;</lang>
- Output:
$ ./romanenc.386 1990 2008 1666 MCMXC MMVIII MDCLXVI
D
<lang d>string toRoman(int n) pure nothrow in {
assert(n < 5000);
} body {
static immutable weights = [1000, 900, 500, 400, 100, 90,
50, 40, 10, 9, 5, 4, 1];
static immutable symbols = ["M","CM","D","CD","C","XC","L",
"XL","X","IX","V","IV","I"];
string roman;
foreach (i, w; weights) {
while (n >= w) {
roman ~= symbols[i];
n -= w;
}
if (n == 0)
break;
}
return roman;
} unittest {
assert(toRoman(455) == "CDLV"); assert(toRoman(3456) == "MMMCDLVI"); assert(toRoman(2488) == "MMCDLXXXVIII");
}
void main() {}</lang>
Delphi
<lang delphi>program RomanNumeralsEncode;
{$APPTYPE CONSOLE}
function IntegerToRoman(aValue: Integer): string; var
i: Integer;
const
WEIGHTS: array[0..12] of Integer = (1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1);
SYMBOLS: array[0..12] of string = ('M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I');
begin
for i := Low(WEIGHTS) to High(WEIGHTS) do
begin
while aValue >= WEIGHTS[i] do
begin
Result := Result + SYMBOLS[i];
aValue := aValue - WEIGHTS[i];
end;
if aValue = 0 then
Break;
end;
end;
begin
Writeln(IntegerToRoman(1990)); // MCMXC Writeln(IntegerToRoman(2008)); // MMVIII Writeln(IntegerToRoman(1666)); // MDCLXVI
end.</lang>
DWScript
<lang delphi>const weights = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]; const symbols = ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"];
function toRoman(n : Integer) : String; var
i, w : Integer;
begin
for i := 0 to weights.High do begin
w := weights[i];
while n >= w do begin
Result += symbols[i];
n -= w;
end;
if n = 0 then Break;
end;
end;
PrintLn(toRoman(455)); PrintLn(toRoman(3456)); PrintLn(toRoman(2488));</lang>
EasyLang
<lang>values[] = [ 1000 900 500 400 100 90 50 40 10 9 5 4 1 ] symbol$[] = [ "M" "CM" "D" "CD" "C" "XC" "L" "XL" "X" "IX" "V" "IV" "I" ] func num2rom num . rom$ .
rom$ = ""
for i range len values[]
while num >= values[i]
rom$ &= symbol$[i]
num -= values[i]
.
.
. call num2rom 1990 r$ print r$ call num2rom 2008 r$ print r$ call num2rom 1666 r$ print r$</lang>
ECL
<lang ECL>RomanEncode(UNSIGNED Int) := FUNCTION
SetWeights := [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]; SetSymbols := ['M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I']; ProcessRec := RECORD UNSIGNED val; STRING Roman; END; dsWeights := DATASET(13,TRANSFORM(ProcessRec,SELF.val := Int, SELF := []));
SymbolStr(i,n,STRING s) := CHOOSE(n+1,,SetSymbols[i],SetSymbols[i]+SetSymbols[i],SetSymbols[i]+SetSymbols[i]+SetSymbols[i],s);
RECORDOF(dsWeights) XF(dsWeights L, dsWeights R, INTEGER C) := TRANSFORM ThisVal := IF(C=1,R.Val,L.Val); IsDone := ThisVal = 0; SELF.Roman := IF(IsDone,L.Roman,L.Roman + SymbolStr(C,ThisVal DIV SetWeights[C],L.Roman)); SELF.val := IF(IsDone,0,ThisVal - ((ThisVal DIV SetWeights[C])*SetWeights[C])); END; i := ITERATE(dsWeights,XF(LEFT,RIGHT,COUNTER)); RETURN i[13].Roman;
END;
RomanEncode(1954); //MCMLIV RomanEncode(1990 ); //MCMXC RomanEncode(2008 ); //MMVIII RomanEncode(1666); //MDCLXVI</lang>
Eiffel
<lang Eiffel>class APPLICATION
create make
feature {NONE} -- Initialization
make local numbers: ARRAY [INTEGER] do numbers := <<1990, 2008, 1666, 3159, 1977, 2010>> -- "MCMXC", "MMVIII", "MDCLXVI", "MMMCLIX", "MCMLXXVII", "MMX" across numbers as n loop print (n.item.out + " in decimal Arabic numerals is " + decimal_to_roman (n.item) + " in Roman numerals.%N") end end
feature -- Roman numerals
decimal_to_roman (a_int: INTEGER): STRING -- Representation of integer `a_int' as Roman numeral require a_int > 0 local dnums: ARRAY[INTEGER] rnums: ARRAY[STRING]
dnum: INTEGER rnum: STRING
i: INTEGER do dnums := <<1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1>> rnums := <<"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I">>
dnum := a_int rnum := ""
from i := 1 until i > dnums.count or dnum <= 0 loop from until dnum < dnums[i] loop dnum := dnum - dnums[i] rnum := rnum + rnums[i] end i := i + 1 end
Result := rnum end end</lang>
Ela
<lang ela>open number string math
digit x y z k =
[[x],[x,x],[x,x,x],[x,y],[y],[y,x],[y,x,x],[y,x,x,x],[x,z]] : (toInt k - 1)
toRoman 0 = "" toRoman x | x < 0 = fail "Negative roman numeral"
| x >= 1000 = 'M' :: toRoman (x - 1000)
| x >= 100 = let (q,r) = x `divrem` 100 in
digit 'C' 'D' 'M' q ++ toRoman r
| x >= 10 = let (q,r) = x `divrem` 10 in
digit 'X' 'L' 'C' q ++ toRoman r
| else = digit 'I' 'V' 'X' x
map (join "" << toRoman) [1999,25,944]</lang>
- Output:
["MCMXCIX","XXV","CMXLIV"]
Elena
ELENA 5.0 : <lang elena>import system'collections; import system'routines; import extensions; import extensions'text;
static RomanDictionary = Dictionary.new()
.setAt(1000, "M")
.setAt(900, "CM")
.setAt(500, "D")
.setAt(400, "CD")
.setAt(100, "C")
.setAt(90, "XC")
.setAt(50, "L")
.setAt(40, "XL")
.setAt(10, "X")
.setAt(9, "IX")
.setAt(5, "V")
.setAt(4, "IV")
.setAt(1, "I");
extension op {
toRoman()
= RomanDictionary.accumulate(new StringWriter("I", self), (m,kv => m.replace(new StringWriter("I",kv.Key), kv.Value)));
}
public program() {
console.printLine("1990 : ", 1990.toRoman());
console.printLine("2008 : ", 2008.toRoman());
console.printLine("1666 : ", 1666.toRoman())
}</lang>
- Output:
1990 : MCMXC 2008 : MMVIII 1666 : MDCLXVI
Elixir
<lang elixir>defmodule Roman_numeral do
def encode(0), do: def encode(x) when x >= 1000, do: [?M | encode(x - 1000)] def encode(x) when x >= 100, do: digit(div(x,100), ?C, ?D, ?M) ++ encode(rem(x,100)) def encode(x) when x >= 10, do: digit(div(x,10), ?X, ?L, ?C) ++ encode(rem(x,10)) def encode(x) when x >= 1, do: digit(x, ?I, ?V, ?X) defp digit(1, x, _, _), do: [x] defp digit(2, x, _, _), do: [x, x] defp digit(3, x, _, _), do: [x, x, x] defp digit(4, x, y, _), do: [x, y] defp digit(5, _, y, _), do: [y] defp digit(6, x, y, _), do: [y, x] defp digit(7, x, y, _), do: [y, x, x] defp digit(8, x, y, _), do: [y, x, x, x] defp digit(9, x, _, z), do: [x, z]
end</lang>
Another:
<lang elixir>defmodule Roman_numeral do
@symbols [ {1000, 'M'}, {900, 'CM'}, {500, 'D'}, {400, 'CD'}, {100, 'C'}, {90, 'XC'},
{50, 'L'}, {40, 'XL'}, {10, 'X'}, {9, 'IX'}, {5, 'V'}, {4, 'IV'}, {1, 'I'} ]
def encode(num) do
{roman,_} = Enum.reduce(@symbols, {[], num}, fn {divisor, letter}, {memo, n} ->
{memo ++ List.duplicate(letter, div(n, divisor)), rem(n, divisor)}
end)
Enum.join(roman)
end
end</lang>
Test: <lang elixir>Enum.each([1990, 2008, 1666], fn n ->
IO.puts "#{n}: #{Roman_numeral.encode(n)}"
end)</lang>
- Output:
1990: MCMXC 2008: MMVIII 1666: MDCLXVI
Emacs Lisp
<lang lisp>(defun ar2ro (AN)
"Translate from arabic number AN to roman number. For example, (ar2ro 1666) returns (M D C L X V I)." (cond ((>= AN 1000) (cons 'M (ar2ro (- AN 1000)))) ((>= AN 900) (cons 'C (cons 'M (ar2ro (- AN 900))))) ((>= AN 500) (cons 'D (ar2ro (- AN 500)))) ((>= AN 400) (cons 'C (cons 'D (ar2ro (- AN 400))))) ((>= AN 100) (cons 'C (ar2ro (- AN 100)))) ((>= AN 90) (cons 'X (cons 'C (ar2ro (- AN 90))))) ((>= AN 50) (cons 'L (ar2ro (- AN 50)))) ((>= AN 40) (cons 'X (cons 'L (ar2ro (- AN 40))))) ((>= AN 10) (cons 'X (ar2ro (- AN 10)))) ((>= AN 5) (cons 'V (ar2ro (- AN 5)))) ((>= AN 4) (cons 'I (cons 'V (ar2ro (- AN 4))))) ((>= AN 1) (cons 'I (ar2ro (- AN 1)))) ((= AN 0) nil)))</lang>
Erlang
<lang erlang>-module(roman). -export([to_roman/1]).
to_roman(0) -> []; to_roman(X) when X >= 1000 -> [$M | to_roman(X - 1000)]; to_roman(X) when X >= 100 ->
digit(X div 100, $C, $D, $M) ++ to_roman(X rem 100);
to_roman(X) when X >= 10 ->
digit(X div 10, $X, $L, $C) ++ to_roman(X rem 10);
to_roman(X) when X >= 1 -> digit(X, $I, $V, $X).
digit(1, X, _, _) -> [X]; digit(2, X, _, _) -> [X, X]; digit(3, X, _, _) -> [X, X, X]; digit(4, X, Y, _) -> [X, Y]; digit(5, _, Y, _) -> [Y]; digit(6, X, Y, _) -> [Y, X]; digit(7, X, Y, _) -> [Y, X, X]; digit(8, X, Y, _) -> [Y, X, X, X]; digit(9, X, _, Z) -> [X, Z].</lang>
sample:
1> c(roman).
{ok,roman}
2> roman:to_roman(1999).
"MCMXCIX"
3> roman:to_roman(25).
"XXV"
4> roman:to_roman(944).
"CMXLIV"
Alternative: <lang erlang> -module( roman_numerals ).
-export( [encode_from_integer/1]).
-record( encode_acc, {n, romans=""} ).
encode_from_integer( N ) when N > 0 ->
#encode_acc{romans=Romans} = lists:foldl( fun encode_from_integer/2, #encode_acc{n=N}, map() ),
Romans.
encode_from_integer( _Map, #encode_acc{n=0}=Acc ) -> Acc;
encode_from_integer( {_Roman, Value}, #encode_acc{n=N}=Acc ) when N < Value -> Acc;
encode_from_integer( {Roman, Value}, #encode_acc{n=N, romans=Romans} ) ->
Times = N div Value,
New_roman = lists:flatten( lists:duplicate(Times, Roman) ),
#encode_acc{n=N - (Times * Value), romans=Romans ++ New_roman}.
map() -> [{"M",1000}, {"CM",900}, {"D",500}, {"CD",400}, {"C",100}, {"XC",90}, {"L",50}, {"XL",40}, {"X",10}, {"IX",9}, {"V",5}, {"IV",4}, {"I\ ",1}]. </lang>
- Output:
36> roman_numerals:encode_from_integer( 1990 ). "MCMXC" 37> roman_numerals:encode_from_integer( 2008 ). "MMVIII" 38> roman_numerals:encode_from_integer( 1666 ). "MDCLXVI"
ERRE
<lang ERRE> PROGRAM ARAB2ROMAN
DIM ARABIC%[12],ROMAN$[12]
PROCEDURE TOROMAN(VALUE->ANS$) LOCAL RESULT$
FOR I%=0 TO 12 DO
WHILE VALUE>=ARABIC%[I%] DO
RESULT$+=ROMAN$[I%]
VALUE-=ARABIC%[I%]
END WHILE
END FOR
ANS$=RESULT$
END PROCEDURE
BEGIN ! !Testing !
ARABIC%[]=(1000,900,500,400,100,90,50,40,10,9,5,4,1)
ROMAN$[]=("M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I")
TOROMAN(2009->ANS$) PRINT("2009 = ";ANS$)
TOROMAN(1666->ANS$) PRINT("1666 = ";ANS$)
TOROMAN(3888->ANS$) PRINT("3888 = ";ANS$)
END PROGRAM </lang>
Euphoria
<lang Euphoria>constant arabic = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 } constant roman = {"M", "CM", "D","CD", "C","XC","L","XL","X","IX","V","IV","I"}
function toRoman(integer val)
sequence result
result = ""
for i = 1 to 13 do
while val >= arabic[i] do
result &= roman[i]
val -= arabic[i]
end while
end for
return result
end function
printf(1,"%d = %s\n",{2009,toRoman(2009)}) printf(1,"%d = %s\n",{1666,toRoman(1666)}) printf(1,"%d = %s\n",{3888,toRoman(3888)})</lang>
- Output:
2009 = MMIX 1666 = MDCLXVI 3888 = MMMDCCCLXXXVIII
Excel
Excel can encode numbers in Roman forms in 5 successively concise forms. These can be indicated from 0 to 4. Type in a cell: <lang Excel> =ROMAN(2013,0) </lang>
It becomes: <lang> MMXIII </lang>
F#
<lang fsharp>let digit x y z = function
1 -> x | 2 -> x + x | 3 -> x + x + x | 4 -> x + y | 5 -> y | 6 -> y + x | 7 -> y + x + x | 8 -> y + x + x + x | 9 -> x + z | _ -> failwith "invalid call to digit"
let rec to_roman acc = function
| x when x >= 1000 -> to_roman (acc + "M") (x - 1000) | x when x >= 100 -> to_roman (acc + digit "C" "D" "M" (x / 100)) (x % 100) | x when x >= 10 -> to_roman (acc + digit "X" "L" "C" (x / 10)) (x % 10) | x when x > 0 -> acc + digit "I" "V" "X" x | 0 -> acc | _ -> failwith "invalid call to_roman (negative input)"
let roman n = to_roman "" n
[<EntryPoint>] let main args =
[1990; 2008; 1666] |> List.map (fun n -> roman n) |> List.iter (printfn "%s") 0</lang>
- Output:
MCMXC MMVIII MDCLXVI
Factor
A roman numeral library ships with Factor. <lang factor>USE: roman ( scratchpad ) 3333 >roman . "mmmcccxxxiii"</lang>
Parts of the implementation:
<lang factor>CONSTANT: roman-digits
{ "m" "cm" "d" "cd" "c" "xc" "l" "xl" "x" "ix" "v" "iv" "i" }
CONSTANT: roman-values
{ 1000 900 500 400 100 90 50 40 10 9 5 4 1 }
ERROR: roman-range-error n ;
- roman-range-check ( n -- n )
dup 1 10000 between? [ roman-range-error ] unless ;
- >roman ( n -- str )
roman-range-check
roman-values roman-digits [
[ /mod swap ] dip <repetition> concat
] 2map "" concat-as nip ;</lang>
FALSE
<lang false>^$." " [$999>][1000- "M"]#
$899> [ 900-"CM"]? $499> [ 500- "D"]? $399> [ 400-"CD"]?
[$ 99>][ 100- "C"]#
$ 89> [ 90-"XC"]? $ 49> [ 50- "L"]? $ 39> [ 40-"XL"]?
[$ 9>][ 10- "X"]#
$ 8> [ 9-"IX"]? $ 4> [ 5- "V"]? $ 3> [ 4-"IV"]?
[$ ][ 1- "I"]#%</lang>
Fan
<lang Fan>**
- converts a number to its roman numeral representation
class RomanNumerals {
private Str digit(Str x, Str y, Str z, Int i)
{
switch (i)
{
case 1: return x
case 2: return x+x
case 3: return x+x+x
case 4: return x+y
case 5: return y
case 6: return y+x
case 7: return y+x+x
case 8: return y+x+x+x
case 9: return x+z
}
return ""
}
Str toRoman(Int i)
{
if (i>=1000) { return "M" + toRoman(i-1000) }
if (i>=100) { return digit("C", "D", "M", i/100) + toRoman(i%100) }
if (i>=10) { return digit("X", "L", "C", i/10) + toRoman(i%10) }
if (i>=1) { return digit("I", "V", "X", i) }
return ""
}
Void main()
{
2000.times |i| { echo("$i = ${toRoman(i)}") }
}
}</lang>
Forth
<lang forth>: vector create ( n -- ) 0 do , loop does> ( n -- ) swap cells + @ execute ; \ these are ( numerals -- numerals )
- ,I dup c@ C, ; : ,V dup 1 + c@ C, ; : ,X dup 2 + c@ C, ;
\ these are ( numerals -- )
- noname ,I ,X drop ; :noname ,V ,I ,I ,I drop ; :noname ,V ,I ,I drop ;
- noname ,V ,I drop ; :noname ,V drop ; :noname ,I ,V drop ;
- noname ,I ,I ,I drop ; :noname ,I ,I drop ; :noname ,I drop ;
' drop ( 0 : no output ) 10 vector ,digit
- roman-rec ( numerals n -- ) 10 /mod dup if >r over 2 + r> recurse else drop then ,digit ;
- roman ( n -- c-addr u )
dup 0 4000 within 0= abort" EX LIMITO!" HERE SWAP s" IVXLCDM" drop swap roman-rec HERE OVER - ;
1999 roman type \ MCMXCIX
25 roman type \ XXV 944 roman type \ CMXLIV</lang>
Alternative implementation <lang forth>create romans 0 , 1 , 5 , 21 , 9 , 2 , 6 , 22 , 86 , 13 ,
does> swap cells + @ ;
- roman-digit ( a1 n1 a2 n2 -- a3)
drop >r romans begin dup while tuck 4 mod 1- chars r@ + c@ over c! char+ swap 4 / repeat r> drop drop
- (split) swap >r /mod r> swap ;
- >roman ( n1 a -- a n2)
tuck 1000 (split) s" M " roman-digit 100 (split) s" CDM" roman-digit 10 (split) s" XLC" roman-digit 1 (split) s" IVX" roman-digit nip over -
create (roman) 16 chars allot
1999 (roman) >roman type cr</lang>
Fortran
<lang fortran>program roman_numerals
implicit none
write (*, '(a)') roman (2009) write (*, '(a)') roman (1666) write (*, '(a)') roman (3888)
contains
function roman (n) result (r)
implicit none integer, intent (in) :: n integer, parameter :: d_max = 13 integer :: d integer :: m integer :: m_div character (32) :: r integer, dimension (d_max), parameter :: d_dec = & & (/1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1/) character (32), dimension (d_max), parameter :: d_rom = & & (/'M ', 'CM', 'D ', 'CD', 'C ', 'XC', 'L ', 'XL', 'X ', 'IX', 'V ', 'IV', 'I '/)
r = m = n do d = 1, d_max m_div = m / d_dec (d) r = trim (r) // repeat (trim (d_rom (d)), m_div) m = m - d_dec (d) * m_div end do
end function roman
end program roman_numerals</lang>
- Output:
MMIX MDCLXVI MMMDCCCLXXXVIII
FreeBASIC
<lang freebasic>' FB 1.05.0 Win64
Function romanEncode(n As Integer) As String
If n < 1 OrElse n > 3999 Then Return "" can only encode numbers in range 1 to 3999
Dim roman1(0 To 2) As String = {"MMM", "MM", "M"}
Dim roman2(0 To 8) As String = {"CM", "DCCC", "DCC", "DC", "D", "CD", "CCC", "CC", "C"}
Dim roman3(0 To 8) As String = {"XC", "LXXX", "LXX", "LX", "L", "XL", "XXX", "XX", "X"}
Dim roman4(0 To 8) As String = {"IX", "VIII", "VII", "VI", "V", "IV", "III", "II", "I"}
Dim As Integer thousands, hundreds, tens, units
thousands = n \ 1000
n Mod= 1000
hundreds = n \ 100
n Mod= 100
tens = n \ 10
units = n Mod 10
Dim roman As String = ""
If thousands > 0 Then roman += roman1(3 - thousands)
If hundreds > 0 Then roman += roman2(9 - hundreds)
If tens > 0 Then roman += roman3(9 - tens)
If units > 0 Then roman += roman4(9 - units)
Return roman
End Function
Dim a(2) As Integer = {1990, 2008, 1666} For i As Integer = 0 To 2
Print a(i); " => "; romanEncode(a(i))
Next
Print Print "Press any key to quit" Sleep</lang>
- Output:
1990 => MCMXC 2008 => MMVIII 1666 => MDCLXVI
FutureBasic
<lang futurebasic>window 1
local fn DecimaltoRoman( decimal as short ) as Str15
short arabic(12)
Str15 roman(12)
long i
Str15 result : result = ""
arabic(0) = 1000 : arabic(1) = 900 : arabic(2) = 500 : arabic(3) = 400
arabic(4) = 100 : arabic(5) = 90 : arabic(6) = 50 : arabic(7) = 40
arabic(8) = 10 : arabic(9) = 9 : arabic(10) = 5 : arabic(11) = 4: arabic(12) = 1
roman(0) = "M" : roman(1) = "CM" : roman(2) = "D" : roman(3) = "CD"
roman(4) = "C" : roman(5) = "XC" : roman(6) = "L" : roman(7) = "XL"
roman(8) = "X" : roman(9) = "IX" : roman(10) = "V" : roman(11) = "IV" : roman(12) = "I"
for i = 0 to 12
while ( decimal >= arabic(i) )
result = result + roman(i)
decimal = decimal - arabic(i)
wend
next i
if result == "" then result = "Zepherium"
end fn = result
print "1990 = "; fn DecimaltoRoman( 1990 ) print "2008 = "; fn DecimaltoRoman( 2008 ) print "2016 = "; fn DecimaltoRoman( 2016 ) print "1666 = "; fn DecimaltoRoman( 1666 ) print "3888 = "; fn DecimaltoRoman( 3888 ) print "1914 = "; fn DecimaltoRoman( 1914 ) print "1000 = "; fn DecimaltoRoman( 1000 ) print " 513 = "; fn DecimaltoRoman( 513 ) print " 33 = "; fn DecimaltoRoman( 33 )
HandleEvents</lang>
Output:
1990 = MCMXC 2008 = MMVIII 2016 = MMXVI 1666 = MDCLXVI 3888 = MMMDCCCLXXXVIII 1914 = MCMXIV 1000 = M 513 = DXIII 33 = XXXIII
Go
For fluff, the unicode overbar is recognized as a factor of 1000, as described in WP.
If you see boxes in the code below, those are supposed to be the Unicode combining overline (U+0305) and look like IVXLCDM. Or, if you see overstruck combinations of letters, that's a different font rendering problem. (If you need roman numerals > 3999 reliably, it might best to stick to chiseling them in stone...) <lang go>package main
import "fmt"
var (
m0 = []string{"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"}
m1 = []string{"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"}
m2 = []string{"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"}
m3 = []string{"", "M", "MM", "MMM", "I̅V̅",
"V̅", "V̅I̅", "V̅I̅I̅", "V̅I̅I̅I̅", "I̅X̅"}
m4 = []string{"", "X̅", "X̅X̅", "X̅X̅X̅", "X̅L̅",
"L̅", "L̅X̅", "L̅X̅X̅", "L̅X̅X̅X̅", "X̅C̅"}
m5 = []string{"", "C̅", "C̅C̅", "C̅C̅C̅", "C̅D̅",
"D̅", "D̅C̅", "D̅C̅C̅", "D̅C̅C̅C̅", "C̅M̅"}
m6 = []string{"", "M̅", "M̅M̅", "M̅M̅M̅"}
)
func formatRoman(n int) (string, bool) {
if n < 1 || n >= 4e6 {
return "", false
}
// this is efficient in Go. the seven operands are evaluated,
// then a single allocation is made of the exact size needed for the result.
return m6[n/1e6] + m5[n%1e6/1e5] + m4[n%1e5/1e4] + m3[n%1e4/1e3] +
m2[n%1e3/1e2] + m1[n%100/10] + m0[n%10],
true
}
func main() {
// show three numbers mentioned in task descriptions
for _, n := range []int{1990, 2008, 1666} {
r, ok := formatRoman(n)
if ok {
fmt.Println(n, "==", r)
} else {
fmt.Println(n, "not representable")
}
}
}</lang>
- Output:
1990 == MCMXC 2008 == MMVIII 1666 == MDCLXVI
Golo
<lang golo>#!/usr/bin/env golosh
This module takes a decimal integer and converts it to a Roman numeral.
module Romannumeralsencode
augment java.lang.Integer {
function digits = |this| {
var remaining = this
let digits = vector[]
while remaining > 0 {
digits: prepend(remaining % 10)
remaining = remaining / 10
}
return digits
}
---- 123: digitsWithPowers() will return [[1, 2], [2, 1], [3, 0]] ---- function digitsWithPowers = |this| -> vector[ [ this: digits(): get(i), (this: digits(): size() - 1) - i ] for (var i = 0, i < this: digits(): size(), i = i + 1) ]
function encode = |this| {
require(this > 0, "the integer must be positive!")
let romanPattern = |digit, powerOf10| -> match {
when digit == 1 then i
when digit == 2 then i + i
when digit == 3 then i + i + i
when digit == 4 then i + v
when digit == 5 then v
when digit == 6 then v + i
when digit == 7 then v + i + i
when digit == 8 then v + i + i + i
when digit == 9 then i + x
otherwise ""
} with {
i, v, x = [
[ "I", "V", "X" ],
[ "X", "L", "C" ],
[ "C", "D", "M" ],
[ "M", "?", "?" ]
]: get(powerOf10)
}
return vector[ romanPattern(digit, power) foreach digit, power in this: digitsWithPowers() ]: join("")
}
}
function main = |args| {
println("1990 == MCMXC? " + (1990: encode() == "MCMXC"))
println("2008 == MMVIII? " + (2008: encode() == "MMVIII"))
println("1666 == MDCLXVI? " + (1666: encode() == "MDCLXVI"))
}</lang>
Groovy
<lang groovy>symbols = [ 1:'I', 4:'IV', 5:'V', 9:'IX', 10:'X', 40:'XL', 50:'L', 90:'XC', 100:'C', 400:'CD', 500:'D', 900:'CM', 1000:'M' ]
def roman(arabic) {
def result = ""
symbols.keySet().sort().reverse().each {
while (arabic >= it) {
arabic-=it
result+=symbols[it]
}
}
return result
} assert roman(1) == 'I' assert roman(2) == 'II' assert roman(4) == 'IV' assert roman(8) == 'VIII' assert roman(16) == 'XVI' assert roman(32) == 'XXXII' assert roman(25) == 'XXV' assert roman(64) == 'LXIV' assert roman(128) == 'CXXVIII' assert roman(256) == 'CCLVI' assert roman(512) == 'DXII' assert roman(954) == 'CMLIV' assert roman(1024) == 'MXXIV' assert roman(1666) == 'MDCLXVI' assert roman(1990) == 'MCMXC' assert roman(2008) == 'MMVIII'</lang>
Haskell
With an explicit decimal digit representation list:
<lang haskell>digit :: Char -> Char -> Char -> Integer -> String digit x y z k =
[[x], [x, x], [x, x, x], [x, y], [y], [y, x], [y, x, x], [y, x, x, x], [x, z]] !! (fromInteger k - 1)
toRoman :: Integer -> String toRoman 0 = "" toRoman x
| x < 0 = error "Negative roman numeral"
toRoman x
| x >= 1000 = 'M' : toRoman (x - 1000)
toRoman x
| x >= 100 = digit 'C' 'D' 'M' q ++ toRoman r where (q, r) = x `divMod` 100
toRoman x
| x >= 10 = digit 'X' 'L' 'C' q ++ toRoman r where (q, r) = x `divMod` 10
toRoman x = digit 'I' 'V' 'X' x
main :: IO () main = print $ toRoman <$> [1999, 25, 944]</lang>
- Output:
["MCMXCIX","XXV","CMXLIV"]
or, defining romanFromInt in terms of mapAccumL
<lang haskell>import Data.Bifunctor (first) import Data.List (mapAccumL) import Data.Tuple (swap)
roman :: Int -> String roman =
romanFromInt $ zip [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1] (words "M CM D CD C XC L XL X IX V IV I")
romanFromInt :: [(Int, String)] -> Int -> String romanFromInt nks n = concat . snd $ mapAccumL go n nks
where go a (v, s) = swap $ first ((>> s) . enumFromTo 1) $ quotRem a v
main :: IO () main = (putStrLn . unlines) (roman <$> [1666, 1990, 2008, 2016, 2018])</lang>
- Output:
MDCLXVI MCMXC MMVIII MMXVI MMXVIII
With the Roman patterns abstracted, and in a simple logic programming idiom:
<lang haskell> module Main where
-- ENCODER FUNCTION --
romanDigits = "IVXLCDM"
-- Meaning and indices of the romanDigits sequence: -- -- magnitude | 1 5 | index -- -----------|-------|------- -- 0 | I V | 0 1 -- 1 | X L | 2 3 -- 2 | C D | 4 5 -- 3 | M | 6 -- -- romanPatterns are index offsets into romanDigits, -- from an index base of 2 * magnitude.
romanPattern 0 = [] -- empty string romanPattern 1 = [0] -- I or X or C or M romanPattern 2 = [0,0] -- II or XX... romanPattern 3 = [0,0,0] -- III... romanPattern 4 = [0,1] -- IV... romanPattern 5 = [1] -- ... romanPattern 6 = [1,0] romanPattern 7 = [1,0,0] romanPattern 8 = [1,0,0,0] romanPattern 9 = [0,2]
encodeValue 0 _ = "" encodeValue value magnitude = encodeValue rest (magnitude + 1) ++ digits
where low = rem value 10 -- least significant digit (encoded now) rest = div value 10 -- the other digits (to be encoded next) indices = map addBase (romanPattern low) addBase i = i + (2 * magnitude) digits = map pickDigit indices pickDigit i = romanDigits!!i
encode value = encodeValue value 0
-- TEST SUITE --
main = do
test "MCMXC" 1990 test "MMVIII" 2008 test "MDCLXVI" 1666
test expected value = putStrLn ((show value) ++ " = " ++ roman ++ remark)
where
roman = encode value
remark =
" (" ++
(if roman == expected then "PASS"
else ("FAIL, expected " ++ (show expected))) ++ ")"
</lang>
- Output:
1990 = MCMXC (PASS) 2008 = MMVIII (PASS) 1666 = MDCLXVI (PASS)
HicEst
<lang hicest>CHARACTER Roman*20
CALL RomanNumeral(1990, Roman) ! MCMXC CALL RomanNumeral(2008, Roman) ! MMVIII CALL RomanNumeral(1666, Roman) ! MDCLXVI
END
SUBROUTINE RomanNumeral( arabic, roman)
CHARACTER roman DIMENSION ddec(13) DATA ddec/1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1/
roman = ' '
todo = arabic
DO d = 1, 13
DO rep = 1, todo / ddec(d)
roman = TRIM(roman) // TRIM(CHAR(d, 13, "M CM D CD C XC L XL X OX V IV I "))
todo = todo - ddec(d)
ENDDO
ENDDO
END</lang>
Icon and Unicon
<lang Icon>link numbers # commas, roman
procedure main(arglist) every x := !arglist do
write(commas(x), " -> ",roman(x)|"*** can't convert to Roman numerals ***")
end</lang>
numbers.icn provides roman as seen below and is based upon a James Gimple SNOBOL4 function.
<lang Icon>procedure roman(n) #: convert integer to Roman numeral
local arabic, result static equiv
initial equiv := ["","I","II","III","IV","V","VI","VII","VIII","IX"]
integer(n) > 0 | fail
result := ""
every arabic := !n do
result := map(result,"IVXLCDM","XLCDM**") || equiv[arabic + 1]
if find("*",result) then fail else return result
end</lang>
- Output:
#roman.exe 3 4 8 49 2010 1666 3000 3999 4000 3 -> III 4 -> IV 8 -> VIII 49 -> XLIX 2,010 -> MMX 1,666 -> MDCLXVI 3,999 -> MMMCMXCIX 4,000 -> *** can't convert to Roman numerals ***
Intercal
INTERCAL outputs numbers as Roman numerals by default, so this is surprisingly trivial for a language that generally tries to make things as difficult as possible. Although you do still have to input the numbers as spelled out digitwise in all caps.
<lang intercal> PLEASE WRITE IN .1
DO READ OUT .1
DO GIVE UP</lang>
- Output:
$ ./roman
ONE SIX SIX SIX
MDCLXVI
Io
<lang Io>Roman := Object clone do (
nums := list(1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1)
rum := list("M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I")
numeral := method(number,
result := ""
for(i, 0, nums size,
if(number == 0, break)
while(number >= nums at(i),
number = number - nums at(i)
result = result .. rum at(i)
)
)
return result
)
)
Roman numeral(1666) println</lang>
J
rfd obtains Roman numerals from decimals.
<lang j>R1000=. ;L:1 ,{ <@(<;._1);._2]0 :0
C CC CCC CD D DC DCC DCCC CM X XX XXX XL L LX LXX LXXX XC I II III IV V VI VII VIII IX
)
rfd=: ('M' $~ <.@%&1000) , R1000 {::~ 1000&|</lang>
Explanation: R1000's definition contains rows representing each of 10 different digits in the 100s, 10s and 1s column (the first entry in each row is blank -- each entry is preceded by a space). R1000 itself represents the first 1000 roman numerals (the cartesian product of these three rows of roman numeral "digits" which is constructed so that they are in numeric order. And the first entry -- zero -- is just blank). To convert a number to its roman numeral representation, we will separate the number into the integer part after dividing by 1000 (that's the number of 'M's we need) and the remainder after dividing by 1000 (which will be an index into R1000).
For example:<lang j> rfd 1234 MCCXXXIV
rfd 567
DLXVII
rfd 89
LXXXIX</lang>
Derived from the J Wiki. Further examples of use will be found there.
Java
The conversion function throws an IllegalArgumentException for non-positive numbers, since Java does not have unsigned primitives.
<lang java5>public class RN {
enum Numeral {
I(1), IV(4), V(5), IX(9), X(10), XL(40), L(50), XC(90), C(100), CD(400), D(500), CM(900), M(1000);
int weight;
Numeral(int weight) {
this.weight = weight;
}
};
public static String roman(long n) {
if( n <= 0) {
throw new IllegalArgumentException();
}
StringBuilder buf = new StringBuilder();
final Numeral[] values = Numeral.values();
for (int i = values.length - 1; i >= 0; i--) {
while (n >= values[i].weight) {
buf.append(values[i]);
n -= values[i].weight;
}
}
return buf.toString();
}
public static void test(long n) {
System.out.println(n + " = " + roman(n));
}
public static void main(String[] args) {
test(1999);
test(25);
test(944);
test(0);
}
}</lang>
- Output:
1999 = MCMXCIX 25 = XXV 944 = CMXLIV Exception in thread "main" java.lang.IllegalArgumentException at RN.roman(RN.java:15) at RN.test(RN.java:31) at RN.main(RN.java:38)
<lang java5>import java.util.Set; import java.util.EnumSet; import java.util.Collections; import java.util.stream.Collectors; import java.util.stream.LongStream;
public interface RomanNumerals {
public enum Numeral {
M(1000), CM(900), D(500), CD(400), C(100), XC(90), L(50), XL(40), X(10), IX(9), V(5), IV(4), I(1);
public final long weight;
private static final Set<Numeral> SET = Collections.unmodifiableSet(EnumSet.allOf(Numeral.class));
private Numeral(long weight) {
this.weight = weight;
}
public static Numeral getLargest(long weight) {
return SET.stream()
.filter(numeral -> weight >= numeral.weight)
.findFirst()
.orElse(I)
;
}
};
public static String encode(long n) {
return LongStream.iterate(n, l -> l - Numeral.getLargest(l).weight)
.limit(Numeral.values().length)
.filter(l -> l > 0)
.mapToObj(Numeral::getLargest)
.map(String::valueOf)
.collect(Collectors.joining())
;
}
public static long decode(String roman) {
long result = new StringBuilder(roman.toUpperCase()).reverse().chars()
.mapToObj(c -> Character.toString((char) c))
.map(numeral -> Enum.valueOf(Numeral.class, numeral))
.mapToLong(numeral -> numeral.weight)
.reduce(0, (a, b) -> a + (a <= b ? b : -b))
;
if (roman.charAt(0) == roman.charAt(1)) {
result += 2 * Enum.valueOf(Numeral.class, roman.substring(0, 1)).weight;
}
return result;
}
public static void test(long n) {
System.out.println(n + " = " + encode(n));
System.out.println(encode(n) + " = " + decode(encode(n)));
}
public static void main(String[] args) {
LongStream.of(1999, 25, 944).forEach(RomanNumerals::test);
}
}</lang>
- Output:
1999 = MCMXCIX MCMXCIX = 1999 25 = XXV XXV = 25 944 = CMXLIV CMXLIV = 944
JavaScript
ES5
Iteration
<lang javascript>var roman = {
map: [
1000, 'M', 900, 'CM', 500, 'D', 400, 'CD', 100, 'C', 90, 'XC',
50, 'L', 40, 'XL', 10, 'X', 9, 'IX', 5, 'V', 4, 'IV', 1, 'I',
],
int_to_roman: function(n) {
var value = ;
for (var idx = 0; n > 0 && idx < this.map.length; idx += 2) {
while (n >= this.map[idx]) {
value += this.map[idx + 1];
n -= this.map[idx];
}
}
return value;
}
}
roman.int_to_roman(1999); // "MCMXCIX"</lang>
Functional composition
<lang JavaScript>(function () {
'use strict';
// If the Roman is a string, pass any delimiters through
// (Int | String) -> String
function romanTranscription(a) {
if (typeof a === 'string') {
var ps = a.split(/\d+/),
dlm = ps.length > 1 ? ps[1] : undefined;
return (dlm ? a.split(dlm)
.map(function (x) {
return Number(x);
}) : [a])
.map(roman)
.join(dlm);
} else return roman(a);
}
// roman :: Int -> String
function roman(n) {
return [[1000, "M"], [900, "CM"], [500, "D"], [400, "CD"], [100,
"C"], [90, "XC"], [50, "L"], [40, "XL"], [10, "X"], [9,
"IX"], [5, "V"], [4, "IV"], [1, "I"]]
.reduce(function (a, lstPair) {
var m = a.remainder,
v = lstPair[0];
return (v > m ? a : {
remainder: m % v,
roman: a.roman + Array(
Math.floor(m / v) + 1
)
.join(lstPair[1])
});
}, {
remainder: n,
roman:
}).roman;
}
// TEST
return [2016, 1990, 2008, "14.09.2015", 2000, 1666].map(
romanTranscription);
})();</lang>
- Output:
<lang JavaScript>["MMXVI", "MCMXC", "MMVIII", "XIV.IX.MMXV", "MM", "MDCLXVI"]</lang>
ES6
Functional
(mapAccumL version) <lang javascript>(() => {
"use strict";
// -------------- ROMAN INTEGER STRINGS --------------
// roman :: Int -> String
const roman = n =>
mapAccumL(residue =>
([k, v]) => second(
q => 0 < q ? (
k.repeat(q)
) : ""
)(remQuot(residue)(v))
)(n)(
zip([
"M", "CM", "D", "CD", "C", "XC",
"L", "XL", "X", "IX", "V", "IV", "I"
])([
1000, 900, 500, 400, 100, 90,
50, 40, 10, 9, 5, 4, 1
])
)[1]
.join("");
// ---------------------- TEST -----------------------
// main :: IO ()
const main = () => (
[2016, 1990, 2008, 2000, 2020, 1666].map(roman)
).join("\n");
// ---------------- GENERIC FUNCTIONS ----------------
// mapAccumL :: (acc -> x -> (acc, y)) -> acc ->
// [x] -> (acc, [y])
const mapAccumL = f =>
// A tuple of an accumulation and a list
// obtained by a combined map and fold,
// with accumulation from left to right.
acc => xs => [...xs].reduce(
(a, x) => {
const tpl = f(a[0])(x);
return [
tpl[0],
a[1].concat(tpl[1])
];
},
[acc, []]
);
// remQuot :: Int -> Int -> (Int, Int)
const remQuot = m =>
n => [m % n, Math.trunc(m / n)];
// second :: (a -> b) -> ((c, a) -> (c, b))
const second = f =>
// A function over a simple value lifted
// to a function over a tuple.
// f (a, b) -> (a, f(b))
xy => [xy[0], f(xy[1])];
// zip :: [a] -> [b] -> [(a, b)]
const zip = xs =>
// The paired members of xs and ys, up to
// the length of the shorter of the two lists.
ys => Array.from({
length: Math.min(xs.length, ys.length)
}, (_, i) => [xs[i], ys[i]]);
// MAIN -- return main();
})();</lang>
- Output:
MDCLXVI MCMXC MMVIII MMXVI MMXVIII MMXX
Declarative
<lang JavaScript>function toRoman(num) {
return 'I' .repeat(num) .replace(/IIIII/g, 'V') .replace(/VV/g, 'X') .replace(/XXXXX/g, 'L') .replace(/LL/g, 'C') .replace(/CCCCC/g, 'D') .replace(/DD/g, 'M') .replace(/VIIII/g, 'IX') .replace(/LXXXX/g, 'XC') .replace(/XXXX/g, 'XL') .replace(/DCCCC/g, 'CM') .replace(/CCCC/g, 'CD') .replace(/IIII/g, 'IV');
}
console.log(toRoman(1666));</lang>
- Output:
<lang JavaScript>MDCLXVI</lang>
jq
Works with gojq, the Go implementation of jq
The "easy-to-code" version is presented first, followed by the "orders of magnitude" version. Both versions work for positive integers up to and including 399,999, but note that the Unicode glyphs for 50,000 and 100,000 are not supported in many environments.
The test cases and output are identical for both versions and are therefore not repeated.
Easy-to-code version
<lang jq>def to_roman_numeral:
def romans:
[100000, "\u2188"],
[90000, "ↂ\u2188"],
[50000, "\u2187"],
[40000, "ↂ\u2187"],
[10000, "ↂ"],
[9000, "Mↂ"],
[5000, "ↁ"],
[4000, "Mↁ"],
[1000, "M"],
[900, "CM"],
[500, "D"],
[400, "CD"],
[100, "C"],
[90, "XC"],
[50, "L"],
[40, "XL"],
[10, "X"],
[9, "IX"],
[5, "V"],
[4, "IV"],
[1, "I"] ;
if . < 1 or . > 399999
then "to_roman_numeral: \(.) is out of range" | error
else reduce romans as [$i, $r] ({n: .};
until (.n < $i;
.res += $r
| .n = .n - $i ) )
| .res
end ;</lang>
Test Cases
<lang jq>def testcases: [1668, 1990, 2008, 2020, 4444, 5000, 8999, 39999, 89999, 399999];
"Decimal => Roman:",
(testcases[] | " \(.) => \(to_roman_numeral)" )</lang>
- Output:
Decimal => Roman: 1668 => MDCLXVIII 1990 => MCMXC 2008 => MMVIII 2020 => MMXX 4444 => MↁCDXLIV 5000 => ↁ 8999 => ↁMMMCMXCIX 39999 => ↂↂↂMↂCMXCIX 89999 => ↇↂↂↂMↂCMXCIX 399999 => ↈↈↈↂↈMↂCMXCIX
"Orders of Magnitude" version
Translated from Julia extended to 399,999 <lang jq>def digits: tostring | explode | map( [.]|implode|tonumber);
- Non-negative integer to Roman numeral up to 399,999
def to_roman_numeral:
if . < 1 or . > 399999
then "to_roman_numeral: \(.) is out of range" | error
else [["I", "X", "C", "M", "ↂ", "\u2188"], ["V", "L", "D", "ↁ", "\u2187"]] as $DR
| (digits|reverse) as $digits
| reduce range(0;$digits|length) as $omag ({rnum: ""};
$digits[$omag] as $d
| if $d == 0 then .omr = ""
elif $d < 4 then .omr = $DR[0][$omag] * $d
elif $d == 4 then .omr = $DR[0][$omag] + $DR[1][$omag]
elif $d == 5 then .omr = $DR[1][$omag]
elif $d < 9 then .omr = $DR[1][$omag] + ($DR[0][$omag] * ($d - 5))
else .omr = $DR[0][$omag] + $DR[0][$omag+1]
end
| .rnum = .omr + .rnum )
| .rnum
end;
</lang>
Jsish
This covers both Encode (toRoman) and Decode (fromRoman).
<lang javascript>/* Roman numerals, in Jsish */ var Roman = {
ord: ['M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I'], val: [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1],
fromRoman: function(roman:string):number {
var n = 0;
var re = /IV|IX|I|V|XC|XL|X|L|CD|CM|C|D|M/g;
var matches = roman.match(re);
if (!matches) return NaN;
for (var hit of matches) n += this.val[this.ord.indexOf(hit)];
return n;
},
toRoman: function(n:number):string {
var roman = ;
var idx = 0;
while (n > 0) {
while (n >= this.val[idx]) {
roman += this.ord[idx];
n -= this.val[idx];
}
idx++;
}
return roman;
}
};
provide('Roman', 1);
if (Interp.conf('unitTest')) {
- Roman.fromRoman('VIII');
- Roman.fromRoman('MMMDIV');
- Roman.fromRoman('CDIV');
- Roman.fromRoman('MDCLXVI');
- Roman.fromRoman('not');
- Roman.toRoman(8);
- Roman.toRoman(3504);
- Roman.toRoman(404);
- Roman.toRoman(1666);
}
/*
!EXPECTSTART!
Roman.fromRoman('VIII') ==> 8 Roman.fromRoman('MMMDIV') ==> 3504 Roman.fromRoman('CDIV') ==> 404 Roman.fromRoman('MDCLXVI') ==> 1666 Roman.fromRoman('not') ==> NaN Roman.toRoman(8) ==> VIII Roman.toRoman(3504) ==> MMMDIV Roman.toRoman(404) ==> CDIV Roman.toRoman(1666) ==> MDCLXVI
!EXPECTEND!
- /</lang>
- Output:
prompt$ jsish -u Roman.jsi [PASS] Roman.jsi
Julia
<lang julia>using Printf
function romanencode(n::Integer)
if n < 1 || n > 4999 throw(DomainError()) end
DR = [["I", "X", "C", "M"] ["V", "L", "D", "MMM"]]
rnum = ""
for (omag, d) in enumerate(digits(n))
if d == 0
omr = ""
elseif d < 4
omr = DR[omag, 1] ^ d
elseif d == 4
omr = DR[omag, 1] * DR[omag, 2]
elseif d == 5
omr = DR[omag, 2]
elseif d < 9
omr = DR[omag, 2] * DR[omag, 1] ^ (d - 5)
else
omr = DR[omag, 1] * DR[omag + 1, 1]
end
rnum = omr * rnum
end
return rnum
end
testcases = [1990, 2008, 1668] append!(testcases, rand(1:4999, 12)) testcases = unique(testcases)
println("Test romanencode, arabic => roman:") for n in testcases
@printf("%-4i => %s\n", n, romanencode(n))
end</lang>
- Output:
Test romanencode, arabic => roman: 1990 => MCMXC 2008 => MMVIII 1668 => MDCLXVIII 2928 => MMCMXXVIII 129 => CXXIX 4217 => MMMMCCXVII 1503 => MDIII 2125 => MMCXXV 1489 => MCDLXXXIX 3677 => MMMDCLXXVII 1465 => MCDLXV 1421 => MCDXXI 1642 => MDCXLII 572 => DLXXII 3714 => MMMDCCXIV
Kotlin
<lang scala>val romanNumerals = mapOf(
1000 to "M", 900 to "CM", 500 to "D", 400 to "CD", 100 to "C", 90 to "XC", 50 to "L", 40 to "XL", 10 to "X", 9 to "IX", 5 to "V", 4 to "IV", 1 to "I"
)
fun encode(number: Int): String? {
if (number > 5000 || number < 1) {
return null
}
var num = number
var result = ""
for ((multiple, numeral) in romanNumerals.entries) {
while (num >= multiple) {
num -= multiple
result += numeral
}
}
return result
}
fun main(args: Array<String>) {
println(encode(1990)) println(encode(1666)) println(encode(2008))
}</lang>
- Output:
MCMXC MDCLXVI MMVIII
Alternatively: <lang scala>fun Int.toRomanNumeral(): String {
fun digit(k: Int, unit: String, five: String, ten: String): String {
return when (k) {
in 1..3 -> unit.repeat(k)
4 -> unit + five
in 5..8 -> five + unit.repeat(k - 5)
9 -> unit + ten
else -> throw IllegalArgumentException("$k not in range 1..9")
}
}
return when (this) {
0 -> ""
in 1..9 -> digit(this, "I", "V", "X")
in 10..99 -> digit(this / 10, "X", "L", "C") + (this % 10).toRomanNumeral()
in 100..999 -> digit(this / 100, "C", "D", "M") + (this % 100).toRomanNumeral()
in 1000..3999 -> "M" + (this - 1000).toRomanNumeral()
else -> throw IllegalArgumentException("${this} not in range 0..3999")
}
}</lang>
Lasso
<lang Lasso>define br => '\r' // encode roman define encodeRoman(num::integer)::string => { local(ref = array('M'=1000, 'CM'=900, 'D'=500, 'CD'=400, 'C'=100, 'XC'=90, 'L'=50, 'XL'=40, 'X'=10, 'IX'=9, 'V'=5, 'IV'=4, 'I'=1)) local(out = string) with i in #ref do => { while(#num >= #i->second) => { #out->append(#i->first) #num -= #i->second } } return #out }
'1990 in roman is '+encodeRoman(1990) br '2008 in roman is '+encodeRoman(2008) br '1666 in roman is '+encodeRoman(1666)</lang>
LaTeX
The macro \Roman is defined for uppercase roman numeral, accepting as argument a name of an existing counter.
<lang latex>\documentclass{minimal} \newcounter{currentyear} \setcounter{currentyear}{\year} \begin{document} Anno Domini \Roman{currentyear} \end{document}</lang>
Liberty BASIC
<lang lb>
dim arabic( 12)
for i =0 to 12
read k
arabic( i) =k
next i
data 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1
dim roman$( 12)
for i =0 to 12
read k$
roman$( i) =k$
next i
data "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"
print 2009, toRoman$( 2009) print 1666, toRoman$( 1666) print 3888, toRoman$( 3888)
end
function toRoman$( value)
i =0
result$ =""
for i = 0 to 12
while value >=arabic( i)
result$ = result$ + roman$( i)
value = value - arabic( i)
wend
next i
toRoman$ =result$
end function </lang>
2009 MMIX 1666 MDCLXVI 3888 MMMDCCCLXXXVIII
LiveCode
<lang LiveCode>function toRoman intNum
local roman,numArabic
put "M,CM,D,CD,C,XC,L,XL,X,IX,V,IV,I" into romans
put "1000,900,500,400,100,90,50,40,10,9,5,4,1" into arabics
put intNum into numArabic
repeat with n = 1 to the number of items of romans
put numArabic div item n of arabics into nums
if nums > 0 then
put repeatChar(item n of romans,nums) after roman
add -(nums * item n of arabics) to numArabic
end if
end repeat
return roman end toRoman
function repeatChar c n
local cc
repeat n times
put c after cc
end repeat
return cc
end repeatChar</lang>
Examples
toRoman(2009) -- MMIX toRoman(1666) -- MDCLXVI toRoman(1984) -- MCMLXXXIV toRoman(3888) -- MMMDCCCLXXXVIII
Logo
<lang logo>make "roman.rules [
[1000 M] [900 CM] [500 D] [400 CD] [ 100 C] [ 90 XC] [ 50 L] [ 40 XL] [ 10 X] [ 9 IX] [ 5 V] [ 4 IV] [ 1 I]
]
to roman :n [:rules :roman.rules] [:acc "||]
if empty? :rules [output :acc] if :n < first first :rules [output (roman :n bf :rules :acc)] output (roman :n - first first :rules :rules word :acc last first :rules)
end</lang>
<lang logo>make "patterns [[?] [? ?] [? ? ?] [? ?2] [?2] [?2 ?] [?2 ? ?] [?2 ? ? ?] [? ?3]]
to digit :d :numerals
if :d = 0 [output "||] output apply (sentence "\( "word (item :d :patterns) "\)) :numerals
end to digits :n :numerals
output word ifelse :n < 10 ["||] [digits int :n/10 bf bf :numerals] ~
digit modulo :n 10 :numerals
end to roman :n
if or :n < 0 :n >= 4000 [output [EX MODVS!]] output digits :n [I V X L C D M]
end
print roman 1999 ; MCMXCIX print roman 25 ; XXV print roman 944 ; CMXLIV</lang>
LOLCODE
<lang lolcode>HAI 1.2 I HAS A Romunz ITZ A BUKKIT Romunz HAS A SRS 0 ITZ "M" Romunz HAS A SRS 1 ITZ "CM" Romunz HAS A SRS 2 ITZ "D" Romunz HAS A SRS 3 ITZ "CD" Romunz HAS A SRS 4 ITZ "C" Romunz HAS A SRS 5 ITZ "XC" Romunz HAS A SRS 6 ITZ "L" Romunz HAS A SRS 7 ITZ "XL" Romunz HAS A SRS 8 ITZ "X" Romunz HAS A SRS 9 ITZ "IX" Romunz HAS A SRS 10 ITZ "V" Romunz HAS A SRS 11 ITZ "IV" Romunz HAS A SRS 12 ITZ "I"
I HAS A Valuez ITZ A BUKKIT Valuez HAS A SRS 0 ITZ 1000 Valuez HAS A SRS 1 ITZ 900 Valuez HAS A SRS 2 ITZ 500 Valuez HAS A SRS 3 ITZ 400 Valuez HAS A SRS 4 ITZ 100 Valuez HAS A SRS 5 ITZ 90 Valuez HAS A SRS 6 ITZ 50 Valuez HAS A SRS 7 ITZ 40 Valuez HAS A SRS 8 ITZ 10 Valuez HAS A SRS 9 ITZ 9 Valuez HAS A SRS 10 ITZ 5 Valuez HAS A SRS 11 ITZ 4 Valuez HAS A SRS 12 ITZ 1
HOW IZ I Romunize YR Num
I HAS A Result ITZ ""
IM IN YR Outer UPPIN YR Dummy TIL BOTH SAEM Num AN 0
IM IN YR Inner UPPIN YR Index TIL BOTH SAEM Index AN 13
BOTH SAEM Num AN BIGGR OF Num AN Valuez'Z SRS Index, O RLY?
YA RLY
Num R DIFF OF Num AN Valuez'Z SRS Index
Result R SMOOSH Result Romunz'Z SRS Index MKAY
GTFO
OIC
IM OUTTA YR Inner
IM OUTTA YR Outer
FOUND YR Result
IF U SAY SO
VISIBLE SMOOSH 2009 " = " I IZ Romunize YR 2009 MKAY MKAY VISIBLE SMOOSH 1666 " = " I IZ Romunize YR 1666 MKAY MKAY VISIBLE SMOOSH 3888 " = " I IZ Romunize YR 3888 MKAY MKAY KTHXBYE</lang>
- Output:
2009 = MMIX 1666 = MDCLXVI 3888 = MMMDCCCLXXXVIII
LotusScript
<lang lss> Function toRoman(value) As String Dim arabic(12) As Integer Dim roman(12) As String
arabic(0) = 1000 arabic(1) = 900 arabic(2) = 500 arabic(3) = 400 arabic(4) = 100 arabic(5) = 90 arabic(6) = 50 arabic(7) = 40 arabic(8) = 10 arabic(9) = 9 arabic(10) = 5 arabic(11) = 4 arabic(12) = 1
roman(0) = "M" roman(1) = "CM" roman(2) = "D" roman(3) = "CD" roman(4) = "C" roman(5) = "XC" roman(6) = "L" roman(7) = "XL" roman(8) = "X" roman(9) = "IX" roman(10) = "V" roman(11) = "IV" roman(12) = "I"
Dim i As Integer, result As String
For i = 0 To 12 Do While value >= arabic(i) result = result + roman(i) value = value - arabic(i) Loop Next i
toRoman = result End Function
</lang>
Lua
<lang lua>romans = { {1000, "M"}, {900, "CM"}, {500, "D"}, {400, "CD"}, {100, "C"}, {90, "XC"}, {50, "L"}, {40, "XL"}, {10, "X"}, {9, "IX"}, {5, "V"}, {4, "IV"}, {1, "I"} }
k = io.read() + 0 for _, v in ipairs(romans) do --note that this is -not- ipairs.
val, let = unpack(v) while k >= val do k = k - val
io.write(let)
end
end print()</lang>
M4
<lang M4>define(`roman',`ifelse(eval($1>=1000),1,`M`'roman(eval($1-1000))', `ifelse(eval($1>=900),1,`CM`'roman(eval($1-900))', `ifelse(eval($1>=500),1,`D`'roman(eval($1-500))', `ifelse(eval($1>=100),1,`C`'roman(eval($1-100))', `ifelse(eval($1>=90),1,`XC`'roman(eval($1-90))', `ifelse(eval($1>=50),1,`L`'roman(eval($1-50))', `ifelse(eval($1>=40),1,`XL`'roman(eval($1-40))', `ifelse(eval($1>=10),1,`X`'roman(eval($1-10))', `ifelse(eval($1>=9),1,`IX`'roman(eval($1-9))', `ifelse(eval($1>=5),1,`V`'roman(eval($1-5))', `ifelse(eval($1>=4),1,`IV`'roman(eval($1-4))', `ifelse(eval($1>=1),1,`I`'roman(eval($1-1))' )')')')')')')')')')')')')dnl dnl roman(3675)</lang>
- Output:
MMMDCLXXV
Maple
<lang Maple>> for n in [ 1666, 1990, 2008 ] do printf( "%d\t%s\n", n, convert( n, 'roman' ) ) end: 1666 MDCLXVI 1990 MCMXC 2008 MMVIII</lang>
Mathematica/Wolfram Language
RomanNumeral is a built-in function in the Wolfram language. Examples: <lang Mathematica>RomanNumeral[4] RomanNumeral[99] RomanNumeral[1337] RomanNumeral[1666] RomanNumeral[6889]</lang> gives back:
IV XCIX MCCCXXXVII MDCLXVI MMMMMMDCCCLXXXIX
Mercury
The non-ceremonial work in this program starts at the function to_roman/1. Unusually for Mercury the function is semi-deterministic. This is because some of the helper functions it calls are also semi-deterministic and the determinism subsystem propagates the status upward. (There are ways to stop it from doing this, but it would distract from the actual Roman numeral conversion process so the semi-determinism has been left in.)
to_roman/1 is just a string of chained function calls. The number is passed in as a string (and the main/2 predicate ensures that it is *only* digits!) is converted into a list of characters. This list is then reversed and the Roman numeral version is built from it. This resulting character list is then converted back into a string and returned.
build_roman/1 takes the lead character off the list (reversed numerals) and then recursively calls itself. It uses the promote/2 predicate to multiply the ensuing Roman numerals (if any) by an order of magnitude and converts the single remaining digit to the appropriate list of Roman numerals. To clarify, if it's passed the number "123" (encoded by this point as ['3', '2', '1']) the following transpires:
- The '3' is removed and
build_roman/1is now called with ['2', '1'].- The '2' is removed and the function is recursively called with ['1'].
- The '1' is removed and the function is recursively called with [] (the empty list)..
- The function returns [].
- The [] has its (non-existent) digits promoted and then gets ['I'] appended (1 converts to ['I'] via
digit_to_roman/1).
- The '1' is removed and the function is recursively called with [] (the empty list)..
- The ['I'] has its (single) digit promoted and is converted to ['X'] and then gets ['I','I'] appended from the 2's conversion. The resulting list is now ['X','I','I'] (or 12).
- The '2' is removed and the function is recursively called with ['1'].
- The ['X','I','I'] has all of its digits promoted, yielding ['C','X','X'] before getting ['I','I','I'] appended. The resulting list is now ['C','X','X','I','I','I'] which is converted into the string "CXXIII" back up in
to_roman/1.
It is possible for this to be implemented differently even keeping the same algorithm. For example the map module from the standard library could be used for looking up conversions and promotions instead of having digit_to_roman/1 and promote. This would require, however, either passing around the conversion tables constantly (bulking up the parameter lists of all functions and predicates) or creating said conversion tables each time at point of use (slowing down the implementation greatly).
Now the semi-determinism of the functions involved is a little bit of a problem. In the main/2 predicate you can see one means of dealing with it. main/2 *must* be deterministic (or cc_multi, but this is equivalent for this discussion). There can be *no* failure in a called function or predicate … unless that failure is explicitly handled somehow. In this implementation the failure is handled in the foldl/4's provided higher-order predicate lambda. The call to to_roman/1 is called within a conditional and both the success (true) and failure (false) branches are handled. This makes the passed-in predicate lambda deterministic, even though the implementation functions and predicates are semi-deterministic.
But why are they semi-deterministic? Well, this has to do with the type system. It doesn't permit sub-typing, so when the type of a predicate is, say pred(char, char) (as is the case for promote/2), the underlying implementation *must* handle *all* values that a type char could possibly hold. It is trivial to see that our code does not. This means that, in theory, it is possible that promote/2 (or digit_to_roman/1) could be passed a value which cannot be processed, thus triggering a false result, and thus being semi-deterministic.
roman.m
<lang Mercury>
- - module roman.
- - interface.
- - import_module io.
- - pred main(io::di, io::uo) is det.
- - implementation.
- - import_module char, int, list, string.
main(!IO) :-
command_line_arguments(Args, !IO),
filter(is_all_digits, Args, CleanArgs),
foldl((pred(Arg::in, !.IO::di, !:IO::uo) is det :-
( Roman = to_roman(Arg) ->
format("%s => %s", [s(Arg), s(Roman)], !IO), nl(!IO)
; format("%s cannot be converted.", [s(Arg)], !IO), nl(!IO) )
), CleanArgs, !IO).
- - func to_roman(string::in) = (string::out) is semidet.
to_roman(Number) = from_char_list(build_roman(reverse(to_char_list(Number)))).
- - func build_roman(list(char)) = list(char).
- - mode build_roman(in) = out is semidet.
build_roman([]) = []. build_roman([D|R]) = Roman :-
map(promote, build_roman(R), Interim), Roman = Interim ++ digit_to_roman(D).
- - func digit_to_roman(char) = list(char).
- - mode digit_to_roman(in) = out is semidet.
digit_to_roman('0') = []. digit_to_roman('1') = ['I']. digit_to_roman('2') = ['I','I']. digit_to_roman('3') = ['I','I','I']. digit_to_roman('4') = ['I','V']. digit_to_roman('5') = ['V']. digit_to_roman('6') = ['V','I']. digit_to_roman('7') = ['V','I','I']. digit_to_roman('8') = ['V','I','I','I']. digit_to_roman('9') = ['I','X'].
- - pred promote(char::in, char::out) is semidet.
promote('I', 'X'). promote('V', 'L'). promote('X', 'C'). promote('L', 'D'). promote('C', 'M').
- - end_module roman.
</lang>
- Output:
$ '''mmc roman && ./roman 1 8 27 64 125 216 343 512 729 1000 1331 1728 2197 2744 3375''' ''1 => I'' ''8 => VIII'' ''27 => XXVII'' ''64 => LXIV'' ''125 => CXXV'' ''216 => CCXVI'' ''343 => CCCXLIII'' ''512 => DXII'' ''729 => DCCXXIX'' ''1000 => M'' ''1331 => MCCCXXXI'' ''1728 => MDCCXXVIII'' ''2197 => MMCXCVII'' ''2744 => MMDCCXLIV'' ''3375 => MMMCCCLXXV''
roman2.m
Another implementation using an algorithm inspired by the Erlang implementation could look like this:
<lang Mercury>
- - module roman2.
- - interface.
- - import_module io.
- - pred main(io::di, io::uo) is det.
- - implementation.
- - import_module char, int, list, string.
main(!IO) :-
command_line_arguments(Args, !IO),
filter_map(to_int, Args, CleanArgs),
foldl((pred(Arg::in, !.IO::di, !:IO::uo) is det :-
( Roman = to_roman(Arg) ->
format("%i => %s",
[i(Arg), s(from_char_list(Roman))], !IO),
nl(!IO)
; format("%i cannot be converted.", [i(Arg)], !IO), nl(!IO) )
), CleanArgs, !IO).
- - func to_roman(int) = list(char).
- - mode to_roman(in) = out is semidet.
to_roman(N) = ( N >= 1000 ->
['M'] ++ to_roman(N - 1000)
;( N >= 100 ->
digit(N / 100, 'C', 'D', 'M') ++ to_roman(N rem 100)
;( N >= 10 ->
digit(N / 10, 'X', 'L', 'C') ++ to_roman(N rem 10)
;( N >= 1 ->
digit(N, 'I', 'V', 'X')
; [] ) ) ) ).
- - func digit(int, char, char, char) = list(char).
- - mode digit(in, in, in, in) = out is semidet.
digit(1, X, _, _) = [X]. digit(2, X, _, _) = [X, X]. digit(3, X, _, _) = [X, X, X]. digit(4, X, Y, _) = [X, Y]. digit(5, _, Y, _) = [Y]. digit(6, X, Y, _) = [Y, X]. digit(7, X, Y, _) = [Y, X, X]. digit(8, X, Y, _) = [Y, X, X, X]. digit(9, X, _, Z) = [X, Z].
- - end_module roman2.
</lang>
This implementation calculates the value of the thousands, then the hundreds, then the tens, then the ones. In each case it uses the digit/4 function and some tricks with unification to build the appropriate list of characters for the digit and multiplier being targeted.
Its output is identical to that of the previous version.
Microsoft Small Basic
<lang microsoftsmallbasic> arabicNumeral = 1990 ConvertToRoman() TextWindow.WriteLine(romanNumeral) 'MCMXC arabicNumeral = 2018 ConvertToRoman() TextWindow.WriteLine(romanNumeral) 'MMXVIII arabicNumeral = 3888 ConvertToRoman() TextWindow.WriteLine(romanNumeral) 'MMMDCCCLXXXVIII
Sub ConvertToRoman
weights[0] = 1000
weights[1] = 900
weights[2] = 500
weights[3] = 400
weights[4] = 100
weights[5] = 90
weights[6] = 50
weights[7] = 40
weights[8] = 10
weights[9] = 9
weights[10] = 5
weights[11] = 4
weights[12] = 1
symbols[0] = "M"
symbols[1] = "CM"
symbols[2] = "D"
symbols[3] = "CD"
symbols[4] = "C"
symbols[5] = "XC"
symbols[6] = "L"
symbols[7] = "XL"
symbols[8] = "X"
symbols[9] = "IX"
symbols[10] = "V"
symbols[11] = "IV"
symbols[12] = "I"
romanNumeral = ""
i = 0
While (i <= 12) And (arabicNumeral > 0)
While arabicNumeral >= weights[i]
romanNumeral = Text.Append(romanNumeral, symbols[i])
arabicNumeral = arabicNumeral - weights[i]
EndWhile
i = i + 1
EndWhile
EndSub </lang>
- Output:
MCMXC MMXVIII MMMDCCCLXXXVIII
Modula-2
<lang modula2> MODULE RomanNumeralsEncode;
FROM Strings IMPORT
Append;
FROM STextIO IMPORT
WriteString, WriteLn;
CONST
MaxChars = 15;
(* 3888 or MMMDCCCLXXXVIII (15 chars) is the longest string properly encoded
with these symbols. *)
TYPE
TRomanNumeral = ARRAY [0 .. MaxChars - 1] OF CHAR;
PROCEDURE ToRoman(AValue: CARDINAL; VAR OUT Destination: ARRAY OF CHAR); TYPE
TRomanSymbols = ARRAY [0 .. 1] OF CHAR; TWeights = ARRAY [0 .. 12] OF CARDINAL; TSymbols = ARRAY [0 .. 12] OF TRomanSymbols;
CONST
Weights = TWeights {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
Symbols = TSymbols {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX",
"V", "IV", "I"};
VAR
I: CARDINAL;
BEGIN
Destination := "";
I := 0;
WHILE (I <= HIGH(Weights)) AND (AValue > 0) DO
WHILE AValue >= Weights[I] DO
Append(Symbols[I], Destination);
AValue := AValue - Weights[I]
END;
INC(I);
END;
END ToRoman;
VAR
Numeral: TRomanNumeral;
BEGIN
ToRoman(1990, Numeral); WriteString(Numeral); WriteLn; (* MCMXC *) ToRoman(2018, Numeral); WriteString(Numeral); WriteLn; (* MMXVIII *) ToRoman(3888, Numeral); WriteString(Numeral); WriteLn; (* MMMDCCCLXXXVIII *)
END RomanNumeralsEncode. </lang>
- Output:
MCMXC MMXVIII MMMDCCCLXXXVIII
MUMPS
<lang MUMPS>TOROMAN(INPUT)
;Converts INPUT into a Roman numeral. INPUT must be an integer between 1 and 3999 ;OUTPUT is the string to return ;I is a loop variable ;CURRVAL is the current value in the loop QUIT:($FIND(INPUT,".")>1)!(INPUT<=0)!(INPUT>3999) "Invalid input" NEW OUTPUT,I,CURRVAL SET OUTPUT="",CURRVAL=INPUT SET:$DATA(ROMANNUM)=0 ROMANNUM="I^IV^V^IX^X^XL^L^XC^C^CD^D^CM^M" SET:$DATA(ROMANVAL)=0 ROMANVAL="1^4^5^9^10^40^50^90^100^400^500^900^1000" FOR I=$LENGTH(ROMANVAL,"^"):-1:1 DO .FOR Q:CURRVAL<$PIECE(ROMANVAL,"^",I) SET OUTPUT=OUTPUT_$PIECE(ROMANNUM,"^",I),CURRVAL=CURRVAL-$PIECE(ROMANVAL,"^",I) KILL I,CURRVAL QUIT OUTPUT</lang>
- Output:
USER>W $$ROMAN^ROSETTA(1666) MDCLXVI USER>W $$TOROMAN^ROSETTA(2010) MMX USER>W $$TOROMAN^ROSETTA(949) CMXLIX USER>W $$TOROMAN^ROSETTA(949.24) Invalid input USER>W $$TOROMAN^ROSETTA(-949) Invalid input
Another variant <lang MUMPS>TOROMAN(n)
;return empty string if input parameter 'n' is not in 1-3999
Quit:(n'?1.4N)!(n'<4000)!'n ""
New r Set r=""
New p Set p=$Length(n)
New j,x
For j=1:1:p Do
. Set x=$Piece("~I~II~III~IV~V~VI~VII~VIII~IX","~",$Extract(n,j)+1)
. Set x=$Translate(x,"IVX",$Piece("IVX~XLC~CDM~M","~",p-j+1))
. Set r=r_x
Quit r</lang>
Nim
<lang nim>import strutils
const nums = [(1000, "M"), (900, "CM"), (500, "D"), (400, "CD"), (100, "C"), (90, "XC"),
(50, "L"), (40, "XL"), (10, "X"), (9, "IX"), (5, "V"), (4, "IV"), (1, "I")]
proc toRoman(n: Positive): string =
var n = n.int for (a, r) in nums: result.add(repeat(r, n div a)) n = n mod a
for i in [1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
25, 30, 40, 50, 60, 69, 70, 80, 90, 99,
100, 200, 300, 400, 500, 600, 666, 700, 800, 900,
1000, 1009, 1444, 1666, 1945, 1997, 1999,
2000, 2008, 2010, 2011, 2500, 3000, 3999]:
echo ($i).align(4), ": ", i.toRoman</lang>
- Output:
1: I 2: II 3: III 4: IV 5: V 6: VI 7: VII 8: VIII 9: IX 10: X 11: XI 12: XII 13: XIII 14: XIV 15: XV 16: XVI 17: XVII 18: XVIII 19: XIX 20: XX 25: XXV 30: XXX 40: XL 50: L 60: LX 69: LXIX 70: LXX 80: LXXX 90: XC 99: XCIX 100: C 200: CC 300: CCC 400: CD 500: D 600: DC 666: DCLXVI 700: DCC 800: DCCC 900: CM 1000: M 1009: MIX 1444: MCDXLIV 1666: MDCLXVI 1945: MCMXLV 1997: MCMXCVII 1999: MCMXCIX 2000: MM 2008: MMVIII 2010: MMX 2011: MMXI 2500: MMD 3000: MMM 3999: MMMCMXCIX
Objeck
<lang objeck> bundle Default {
class Roman {
nums: static : Int[];
rum : static : String[];
function : Init() ~ Nil {
nums := [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];
rum := ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"];
}
function : native : ToRoman(number : Int) ~ String {
result := "";
for(i :=0; i < nums->Size(); i += 1;) {
while(number >= nums[i]) {
result->Append(rum[i]);
number -= nums[i];
};
};
return result; }
function : Main(args : String[]) ~ Nil {
Init();
ToRoman(1999)->PrintLine();
ToRoman(25)->PrintLine();
ToRoman(944)->PrintLine();
}
}
} </lang>
OCaml
With an explicit decimal digit representation list:
<lang ocaml>let digit x y z = function
1 -> [x] | 2 -> [x;x] | 3 -> [x;x;x] | 4 -> [x;y] | 5 -> [y] | 6 -> [y;x] | 7 -> [y;x;x] | 8 -> [y;x;x;x] | 9 -> [x;z]
let rec to_roman x =
if x = 0 then [] else if x < 0 then invalid_arg "Negative roman numeral" else if x >= 1000 then 'M' :: to_roman (x - 1000) else if x >= 100 then digit 'C' 'D' 'M' (x / 100) @ to_roman (x mod 100) else if x >= 10 then digit 'X' 'L' 'C' (x / 10) @ to_roman (x mod 10) else digit 'I' 'V' 'X' x</lang>
- Output:
# to_roman 1999;; - : char list = ['M'; 'C'; 'M'; 'X'; 'C'; 'I'; 'X'] # to_roman 25;; - : char list = ['X'; 'X'; 'V'] # to_roman 944;; - : char list = ['C'; 'M'; 'X'; 'L'; 'I'; 'V']
Oforth
<lang Oforth>[ [1000,"M"], [900,"CM"], [500,"D"], [400,"CD"], [100,"C"], [90,"XC"], [50,"L"], [40,"XL"], [10,"X"], [9,"IX"], [5,"V"], [4,"IV"], [1,"I"] ] const: Romans
- roman(n)
| r |
StringBuffer new Romans forEach: r [ while(r first n <=) [ r second << n r first - ->n ] ] ;</lang>
OpenEdge/Progress
<lang progress>FUNCTION encodeRoman RETURNS CHAR (
i_i AS INT
):
DEF VAR cresult AS CHAR. DEF VAR croman AS CHAR EXTENT 7 INIT [ "M", "D", "C", "L", "X", "V", "I" ]. DEF VAR idecimal AS INT EXTENT 7 INIT [ 1000, 500, 100, 50, 10, 5, 1 ]. DEF VAR ipos AS INT INIT 1. DO WHILE i_i > 0:
IF i_i - idecimal[ ipos ] >= 0 THEN
ASSIGN
cresult = cresult + croman[ ipos ]
i_i = i_i - idecimal[ ipos ]
.
ELSE IF ipos < EXTENT( croman ) - 1 AND i_i - ( idecimal[ ipos ] - idecimal[ ipos + 2 ] ) >= 0 THEN
ASSIGN
cresult = cresult + croman[ ipos + 2 ] + croman[ ipos ]
i_i = i_i - ( idecimal[ ipos ] - idecimal[ ipos + 2 ] )
ipos = ipos + 1
.
ELSE
ipos = ipos + 1.
END.
RETURN cresult.
END FUNCTION. /* encodeRoman */
MESSAGE
1990 encodeRoman( 1990 ) SKIP 2008 encodeRoman( 2008 ) SKIP 2000 encodeRoman( 2000 ) SKIP 1666 encodeRoman( 1666 ) SKIP
VIEW-AS ALERT-BOX. </lang>
- Output:
--------------------------- Message (Press HELP to view stack trace) --------------------------- 1990 MCMXC 2008 MMVIII 2000 MM 1666 MDCLXVI --------------------------- OK Help ---------------------------
Oz
<lang oz>declare
fun {Digit X Y Z K}
unit([X] [X X] [X X X] [X Y] [Y] [Y X] [Y X X] [Y X X X] [X Z])
.K
end
fun {ToRoman X}
if X == 0 then ""
elseif X < 0 then raise toRoman(negativeInput X) end
elseif X >= 1000 then "M"#{ToRoman X-1000}
elseif X >= 100 then {Digit &C &D &M X div 100}#{ToRoman X mod 100}
elseif X >= 10 then {Digit &X &L &C X div 10}#{ToRoman X mod 10}
else {Digit &I &V &X X}
end
end
in
{ForAll {Map [1999 25 944] ToRoman} System.showInfo}</lang>
PARI/GP
Old-style Roman numerals <lang parigp>oldRoman(n)={
while(n>999999,
n-=1000000;
print1("((((I))))")
);
if(n>499999,
n-=500000;
print1("I))))")
);
while(n>99999,
n-=100000;
print1("(((I)))")
);
if(n>49999,
n-=50000;
print1("I)))")
);
while(n>9999,
n-=10000;
print1("((I))")
);
if(n>4999,
n-=5000;
print1("I))")
);
while(n>999,
n-=1000;
print1("(I)")
);
if(n>499,
n-=500;
print1("I)")
);
while(n>99,
n-=100;
print1("C")
);
if(n>49,
n-=50;
print1("L");
);
while(n>9,
n-=10;
print1("X")
);
if(n>4,
n-=5;
print1("V");
);
while(n,
n--;
print1("I")
);
print()
};</lang>
This simple version of medieval Roman numerals does not handle large numbers. <lang parigp>medievalRoman(n)={
while(n>999,
n-=1000;
print1("M")
);
if(n>899,
n-=900;
print1("CM")
);
if(n>499,
n-=500;
print1("D")
);
if(n>399,
n-=400;
print1("CD")
);
while(n>99,
n-=100;
print1("C")
);
if(n>89,
n-=90;
print1("XC")
);
if(n>49,
n-=50;
print1("L")
);
if(n>39,
n-=40;
print1("XL")
);
while(n>9,
n-=10;
print1("X")
);
if(n>8,
n-=9;
print1("IX")
);
if(n>4,
n-=5;
print1("V")
);
if(n>3,
n-=4;
print1("IV")
);
while(n,
n--;
print1("I")
);
print()
};</lang>
Pascal
See Delphi
Peloton
Roman numbers are built in to Peloton as a particular form of national number. However, for the sake of the task the _RO opcode has been defined. <lang sgml><@ DEFUDOLITLIT>_RO|__Transformer|<@ DEFKEYPAR>__NationalNumericID|2</@><@ LETRESCS%NNMPAR>...|1</@></@>
<@ ENU$$DLSTLITLIT>1990,2008,1,2,64,124,1666,10001|,| <@ SAYELTLST>...</@> is <@ SAY_ROELTLSTLIT>...|RomanLowerUnicode</@> <@ SAY_ROELTLSTLIT>...|RomanUpperUnicode</@> <@ SAY_ROELTLSTLIT>...|RomanASCII</@> </@></lang>
Same code in padded-out, variable-length English dialect <lang sgml><# DEFINE USERDEFINEDOPCODE LITERAL LITERAL>_RO|__Transformer|<# DEFINE KEYWORD PARAMETER>__NationalNumericID|2</#><# LET RESULT CAST NATIONALNUMBER PARAMETER>...|1</#></#>
<# ENUMERATION LAMBDASPECIFIEDDELMITER LIST LITERAL LITERAL>1990,2008,1,2,64,124,1666,10001|,| <# SAY ELEMENT LIST>...</#> is <# SAY _RO ELEMENT LIST LITERAL>...|RomanLowerUnicode</#> <# SAY _RO ELEMENT LIST LITERAL>...|RomanUpperUnicode</#> <# SAY _RO ELEMENT LIST LITERAL>...|RomanASCII</#> </#></lang>
- Output:
Notice here the three different ways of representing the results.
For reasons for notational differences, see wp:Roman_numerals#Alternate_forms
1990 is ⅿⅽⅿⅹⅽ ⅯⅭⅯⅩⅭ MCMXC 2008 is ⅿⅿⅷ ⅯⅯⅧ MMVIII 1 is ⅰ Ⅰ I 2 is ⅱ Ⅱ II 64 is ⅼⅹⅳ ⅬⅩⅣ LXIV 124 is ⅽⅹⅹⅳ ⅭⅩⅩⅣ CXXIV 1666 is ⅿⅾⅽⅼⅹⅵ ⅯⅮⅭⅬⅩⅥ MDCLXVI 10001 is ⅿⅿⅿⅿⅿⅿⅿⅿⅿⅿⅰ ↂⅠ MMMMMMMMMMI
Perl
Simple program
Simple, fast, produces same output as the Math::Roman module and the Raku example, less crazy than writing a Latin program, and doesn't require experimental modules like the Raku translation. <lang perl>my @symbols = ( [1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I'] );
sub roman {
my($n, $r) = (shift, );
($r, $n) = ('-', -$n) if $n < 0; # Optional handling of negative input
foreach my $s (@symbols) {
my($arabic, $roman) = @$s;
($r, $n) = ($r .= $roman x int($n/$arabic), $n % $arabic)
if $n >= $arabic;
}
$r;
}
say roman($_) for 1..2012;</lang>
Using a module
<lang perl>use Math::Roman qw/roman/; say roman($_) for 1..2012'</lang>
Ported version of Raku
<lang perl>use List::MoreUtils qw( natatime );
my %symbols = (
1 => "I", 5 => "V", 10 => "X", 50 => "L", 100 => "C", 500 => "D", 1_000 => "M"
);
my @subtractors = (
1_000, 100, 500, 100, 100, 10, 50, 10, 10, 1, 5, 1, 1, 0
);
sub roman {
return if 0 == (my $n = shift);
my $iter = natatime 2, @subtractors;
while( my ($cut, $minus) = $iter->() ) {
$n >= $cut
and return $symbols{$cut} . roman($n - $cut);
$n >= $cut - $minus
and return $symbols{$minus} . roman($n + $minus);
}
};
print roman($_) . "\n" for 1..2012;</lang>
Phix
function toRoman(integer v) constant roman = {"M", "CM", "D","CD", "C","XC","L","XL","X","IX","V","IV","I"}, decml = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 } string res = "" integer val = v for i=1 to length(roman) do while val>=decml[i] do res &= roman[i] val -= decml[i] end while end for -- return res return {v,res} -- (for output) end function ?apply({1990,2008,1666},toRoman)
- Output:
{{1990,"MCMXC"},{2008,"MMVIII"},{1666,"MDCLXVI"}}
Phixmonti
<lang Phixmonti>include ..\Utilitys.pmt
def romanEnc /# n -- s #/
var number
"" var res
( ( 1000 "M" ) ( 900 "CM" ) ( 500 "D" ) ( 400 "CD" ) ( 100 "C" ) ( 90 "XC" )
( 50 "L" ) ( 40 "XL" ) ( 10 "X" ) ( 9 "IX" ) ( 5 "V" ) ( 4 "IV" ) ( 1 "I" ) )
len for
get 1 get
number over / int
number rot mod var number
swap 2 get rot dup if
for drop res over chain var res endfor
else
drop
endif
drop drop
endfor
drop
res
enddef
1968 romanEnc print</lang>
<lang Phixmonti>def romanEnc /# n -- s #/
var k
( ( 1000 "M" ) ( 900 "CM" ) ( 500 "D" ) ( 400 "CD" ) ( 100 "C" ) ( 90 "XC" )
( 50 "L" ) ( 40 "XL" ) ( 10 "X" ) ( 9 "IX" ) ( 5 "V" ) ( 4 "IV" ) ( 1 "I" ) )
len for
get 2 get var let 1 get var val drop
k val >=
while
k val - var k
let print
k val >=
endwhile
endfor
drop nl
enddef
1968 romanEnc</lang> Without vars <lang Phixmonti>def romanEnc /# n -- s #/
>ps
( ( 1000 "M" ) ( 900 "CM" ) ( 500 "D" ) ( 400 "CD" ) ( 100 "C" ) ( 90 "XC" )
( 50 "L" ) ( 40 "XL" ) ( 10 "X" ) ( 9 "IX" ) ( 5 "V" ) ( 4 "IV" ) ( 1 "I" ) )
len for
get 2 get swap 1 get nip
tps over >=
while
ps> over - >ps
over print
tps over >=
endwhile
drop drop
endfor
ps> drop drop nl
enddef
1968 romanEnc</lang>
PHP
<lang php> /**
* int2roman * Convert any positive value of a 32-bit signed integer to its modern roman * numeral representation. Numerals within parentheses are multiplied by * 1000. ie. M == 1 000, (M) == 1 000 000, ((M)) == 1 000 000 000 * * @param number - an integer between 1 and 2147483647 * @return roman numeral representation of number */
function int2roman($number) { if (!is_int($number) || $number < 1) return false; // ignore negative numbers and zero
$integers = array(900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1); $numerals = array('CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I'); $major = intval($number / 1000) * 1000; $minor = $number - $major; $numeral = $leastSig = ;
for ($i = 0; $i < sizeof($integers); $i++) { while ($minor >= $integers[$i]) { $leastSig .= $numerals[$i]; $minor -= $integers[$i]; } }
if ($number >= 1000 && $number < 40000) { if ($major >= 10000) { $numeral .= '('; while ($major >= 10000) { $numeral .= 'X'; $major -= 10000; } $numeral .= ')'; } if ($major == 9000) { $numeral .= 'M(X)'; return $numeral . $leastSig; } if ($major == 4000) { $numeral .= 'M(V)'; return $numeral . $leastSig; } if ($major >= 5000) { $numeral .= '(V)'; $major -= 5000; } while ($major >= 1000) { $numeral .= 'M'; $major -= 1000; } }
if ($number >= 40000) { $major = $major/1000; $numeral .= '(' . int2roman($major) . ')'; }
return $numeral . $leastSig; } </lang>
Picat
<lang Picat>go =>
List = [455,999,1990,1999,2000,2001,2008,2009,2010,2011,2012,1666,3456,3888,4000],
foreach(Val in List)
printf("%4d: %w\n", Val, roman_encode(Val))
end,
nl.
roman_encode(Val) = Res =>
if Val <= 0 then
Res := -1
else
Arabic = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1],
Roman = ["M", "CM", "D", "CD", "C", "XC","L","XL","X","IX","V","IV","I"],
Res = "",
foreach(I in 1..Arabic.length)
while(Val >= Arabic[I])
Res := Res ++ Roman[I],
Val := Val - Arabic[I]
end
end
end.</lang>
- Output:
455: CDLV 999: CMXCIX 1990: MCMXC 1999: MCMXCIX 2000: MM 2001: MMI 2008: MMVIII 2009: MMIX 2010: MMX 2011: MMXI 2012: MMXII 1666: MDCLXVI 3456: MMMCDLVI 3888: MMMDCCCLXXXVIII 4000: MMMM
Longest numeral
Which number encodes to the longest Roman numerals in the interval 1..4000: <lang Picat>go2 =>
All = [Len=I=roman_encode(I) : I in 1..4000,E=roman_encode(I), Len=E.len].sort_down, println(All[1..2]), nl.</lang>
- Output:
[15 = 3888 = MMMDCCCLXXXVIII,14 = 3887 = MMMDCCCLXXXVII]
PicoLisp
<lang PicoLisp>(de roman (N)
(pack
(make
(mapc
'((C D)
(while (>= N D)
(dec 'N D)
(link C) ) )
'(M CM D CD C XC L XL X IX V IV I)
(1000 900 500 400 100 90 50 40 10 9 5 4 1) ) ) ) )</lang>
- Output:
: (roman 1009) -> "MIX" : (roman 1666) -> "MDCLXVI"
Pike
<lang pike>import String; int main(){
write(int2roman(2009) + "\n"); write(int2roman(1666) + "\n"); write(int2roman(1337) + "\n");
}</lang>
PL/I
<lang PL/I> /* From Wiki Fortran */ roman: procedure (n) returns(character (32) varying);
declare n fixed binary nonassignable;
declare (d, m) fixed binary;
declare (r, m_div) character (32) varying;
declare d_dec(13) fixed binary static initial
(1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1);
declare d_rom(13) character (2) varying static initial
('M', 'CM', 'D', 'CD', 'C', 'XC', 'L',
'XL', 'X', 'IX', 'V', 'IV', 'I');
r = ;
m = n;
do d = 1 to 13;
m_div = m / d_dec (d);
r = r || copy (d_rom (d), m_div);
m = m - d_dec (d) * m_div;
end;
return (r);
end roman; </lang> Results:
11 XI 1990 MCMXC 2008 MMVIII 1666 MDCLXVI 1999 MCMXCIX
PL/SQL
<lang PL/SQL>
/*****************************************************************
* $Author: Atanas Kebedjiev $ ***************************************************************** * Encoding an Arabic numeral to a Roman in the range 1..3999 is much simpler as Oracle provides the conversion formats. * Please see also the SQL solution for the same task. */
CREATE OR REPLACE FUNCTION rencode(an IN NUMBER)
RETURN VARCHAR2
IS BEGIN
RETURN to_char(an, 'RN');
END rencode;
BEGIN
DBMS_OUTPUT.PUT_LINE ('2012 = ' || rencode('2012')); -- MMXII
DBMS_OUTPUT.PUT_LINE ('1951 = ' || rencode('1951')); -- MCMLI
DBMS_OUTPUT.PUT_LINE ('1987 = ' || rencode('1987')); -- MCMLXXXVII
DBMS_OUTPUT.PUT_LINE ('1666 = ' || rencode('1666')); -- MDCLXVI
DBMS_OUTPUT.PUT_LINE ('1999 = ' || rencode('1999')); -- MCMXCIX
END; </lang>
Plain TeX
TeX has its own way to convert a number into roman numeral, but it produces lowercase letters; the following macro (and usage example), produce uppercase roman numeral.
<lang tex>\def\upperroman#1{\uppercase\expandafter{\romannumeral#1}} Anno Domini \upperroman{\year} \bye</lang>
PowerBASIC
<lang powerbasic>FUNCTION toRoman(value AS INTEGER) AS STRING
DIM arabic(0 TO 12) AS INTEGER DIM roman(0 TO 12) AS STRING ARRAY ASSIGN arabic() = 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 ARRAY ASSIGN roman() = "M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"
DIM i AS INTEGER DIM result AS STRING
FOR i = 0 TO 12
DO WHILE value >= arabic(i)
result = result & roman(i)
value = value - arabic(i)
LOOP
NEXT i
toRoman = result
END FUNCTION
FUNCTION PBMAIN
'Testing ? "2009 = " & toRoman(2009) ? "1666 = " & toRoman(1666) ? "3888 = " & toRoman(3888)
END FUNCTION</lang>
PowerShell
<lang PowerShell> Filter ToRoman { $output =
if ($_ -ge 4000) { throw 'Number too high' }
$current = 1000 $subtractor = 'M' $whole = $False $decimal = $_ 'C','D','X','L','I','V',' ' ` | %{ $divisor = $current if ($whole = !$whole) { $current /= 10 $subtractor = $_ + $subtractor[0] $_ = $subtractor[1] } else { $divisor *= 5 $subtractor = $subtractor[0] + $_ }
$multiple = [Math]::floor($decimal / $divisor) if ($multiple) { $output += [string]$_ * $multiple $decimal %= $divisor } if ($decimal -ge ($divisor -= $current)) { $output += $subtractor $decimal -= $divisor } }
$output } </lang> <lang PowerShell> 19,4,0,2479,3001 | ToRoman </lang>
- Output:
XIX IV MMCDLXXIX MMMI
Prolog
Library clpfd assures that the program works in both managements : Roman towards Arabic and Arabic towards Roman. <lang Prolog>:- use_module(library(clpfd)).
roman :- LA = [ _ , 2010, _, 1449, _], LR = ['MDCCLXXXIX', _ , 'CX', _, 'MDCLXVI'], maplist(roman, LA, LR), maplist(my_print,LA, LR).
roman(A, R) :-
A #> 0,
roman(A, [u, t, h, th], LR, []),
label([A]),
parse_Roman(CR, LR, []),
atom_chars(R, CR).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % using DCG
roman(0, []) --> [].
roman(N, [H | T]) --> {N1 #= N / 10, N2 #= N mod 10}, roman(N1, T), unity(N2, H).
unity(1, u) --> ['I']. unity(1, t) --> ['X']. unity(1, h) --> ['C']. unity(1, th)--> ['M'].
unity(4, u) --> ['IV']. unity(4, t) --> ['XL']. unity(4, h) --> ['CD']. unity(4, th)--> ['MMMM'].
unity(5, u) --> ['V']. unity(5, t) --> ['L']. unity(5, h) --> ['D']. unity(5, th)--> ['MMMMM'].
unity(9, u) --> ['IX']. unity(9, t) --> ['XC']. unity(9, h) --> ['CM']. unity(9, th)--> ['MMMMMMMMM'].
unity(0, _) --> [].
unity(V, U)-->
{V #> 5,
V1 #= V - 5},
unity(5, U),
unity(V1, U).
unity(V, U) --> {V #> 1, V #< 4, V1 #= V-1}, unity(1, U), unity(V1, U).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Extraction of roman "lexeme" parse_Roman(['C','M'|T]) --> ['CM'], parse_Roman(T).
parse_Roman(['C','D'|T]) --> ['CD'], parse_Roman(T).
parse_Roman(['X','C'| T]) --> ['XC'], parse_Roman(T).
parse_Roman(['X','L'| T]) -->
['XL'],
parse_Roman(T).
parse_Roman(['I','X'| T]) -->
['IX'],
parse_Roman(T).
parse_Roman(['I','V'| T]) -->
['IV'],
parse_Roman(T).
parse_Roman([H | T]) --> [H], parse_Roman(T).
parse_Roman([]) -->
[].
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% my_print(A, R) :- format('~w in roman is ~w~n', [A, R]). </lang>
- Output:
?- roman. 1789 in roman is MDCCLXXXIX 2010 in roman is MMX 110 in roman is CX 1449 in roman is MCDXLIX 1666 in roman is MDCLXVI true .
PureBasic
<lang PureBasic>#SymbolCount = 12 ;0 based count DataSection
denominations: Data.s "M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I" ;0-12 denomValues: Data.i 1000,900,500,400,100,90,50,40,10,9,5,4,1 ;values in decending sequential order
EndDataSection
- -setup
Structure romanNumeral
symbol.s value.i
EndStructure
Global Dim refRomanNum.romanNumeral(#SymbolCount)
Restore denominations For i = 0 To #SymbolCount
Read.s refRomanNum(i)\symbol
Next
Restore denomValues For i = 0 To #SymbolCount
Read refRomanNum(i)\value
Next
Procedure.s decRoman(n)
;converts a decimal number to a roman numeral
Protected roman$, i
For i = 0 To #SymbolCount
Repeat
If n >= refRomanNum(i)\value
roman$ + refRomanNum(i)\symbol
n - refRomanNum(i)\value
Else
Break
EndIf
ForEver
Next
ProcedureReturn roman$
EndProcedure
If OpenConsole()
PrintN(decRoman(1999)) ;MCMXCIX PrintN(decRoman(1666)) ;MDCLXVI PrintN(decRoman(25)) ;XXV PrintN(decRoman(954)) ;CMLIV
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit") Input() CloseConsole()
EndIf</lang>
Python
Pythonic
<lang python>import roman print(roman.toRoman(2022))</lang>
Imperative
- Version for Python 2
<lang python>roman = "MDCLXVmdclxvi"; # UPPERCASE for thousands # adjust_roman = "CCXXmmccxxii"; arabic = (1000000, 500000, 100000, 50000, 10000, 5000, 1000, 500, 100, 50, 10, 5, 1); adjust_arabic = (100000, 100000, 10000, 10000, 1000, 1000, 100, 100, 10, 10, 1, 1, 0);
def arabic_to_roman(dclxvi):
org = dclxvi; # 666 #
out = "";
for scale,arabic_scale in enumerate(arabic):
if org == 0: break
multiples = org / arabic_scale;
org -= arabic_scale * multiples;
out += roman[scale] * multiples;
if org >= -adjust_arabic[scale] + arabic_scale:
org -= -adjust_arabic[scale] + arabic_scale;
out += adjust_roman[scale] + roman[scale]
return out
if __name__ == "__main__":
test = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,25,30,40,50,60,69,70,
80,90,99,100,200,300,400,500,600,666,700,800,900,1000,1009,1444,1666,1945,1997,1999,
2000,2008,2500,3000,4000,4999,5000,6666,10000,50000,100000,500000,1000000);
for val in test:
print '%d - %s'%(val, arabic_to_roman(val))</lang>
An alternative which uses the divmod() function<lang python>romanDgts= 'ivxlcdmVXLCDM_'
def ToRoman(num):
namoR =
if num >=4000000:
print 'Too Big -'
return '-----'
for rdix in range(0, len(romanDgts), 2):
if num==0: break
num,r = divmod(num,10)
v,r = divmod(r, 5)
if r==4:
namoR += romanDgts[rdix+1+v] + romanDgts[rdix]
else:
namoR += r*romanDgts[rdix] + (romanDgts[rdix+1] if(v==1) else )
return namoR[-1::-1]</lang>
It is more Pythonic to use zip to iterate over two lists together: <lang python>anums = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1] rnums = "M CM D CD C XC L XL X IX V IV I".split()
def to_roman(x):
ret = []
for a,r in zip(anums, rnums):
n,x = divmod(x,a)
ret.append(r*n)
return .join(ret)
if __name__ == "__main__":
test = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,25,30,40,
50,60,69,70,80,90,99,100,200,300,400,500,600,666,700,800,900,
1000,1009,1444,1666,1945,1997,1999,2000,2008,2010,2011,2500,
3000,3999)
for val in test:
print '%d - %s'%(val, to_roman(val))
</lang>
- Version for Python 3
<lang python>def arabic_to_roman(dclxvi):
- ===========================
Convert an integer from the decimal notation to the Roman notation
org = dclxvi; # 666 #
out = "";
for scale, arabic_scale in enumerate(arabic):
if org == 0: break
multiples = org // arabic_scale;
org -= arabic_scale * multiples;
out += roman[scale] * multiples;
if (org >= -adjust_arabic[scale] + arabic_scale):
org -= -adjust_arabic[scale] + arabic_scale;
out += adjust_roman[scale] + roman[scale]
return out
if __name__ == "__main__":
test = (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,25,30,40,50,60,69,70,
80,90,99,100,200,300,400,500,600,666,700,800,900,1000,1009,1444,1666,1945,1997,1999,
2000,2008,2500,3000,4000,4999,5000,6666,10000,50000,100000,500000,1000000);
for val in test:
print("%8d %s" %(val, arabic_to_roman(val)))</lang>
Declarative
Less readable, but a 'one liner': <lang python>rnl = [ { '4' : 'MMMM', '3' : 'MMM', '2' : 'MM', '1' : 'M', '0' : }, { '9' : 'CM', '8' : 'DCCC', '7' : 'DCC',
'6' : 'DC', '5' : 'D', '4' : 'CD', '3' : 'CCC', '2' : 'CC', '1' : 'C', '0' : }, { '9' : 'XC',
'8' : 'LXXX', '7' : 'LXX', '6' : 'LX', '5' : 'L', '4' : 'XL', '3' : 'XXX', '2' : 'XX', '1' : 'X',
'0' : }, { '9' : 'IX', '8' : 'VIII', '7' : 'VII', '6' : 'VI', '5' : 'V', '4' : 'IV', '3' : 'III',
'2' : 'II', '1' : 'I', '0' : }]
- Option 1
def number2romannumeral(n):
return .join([rnl[x][y] for x, y in zip(range(4), str(n).zfill(4)) if n < 5000 and n > -1])
- Option 2
def number2romannumeral(n):
return reduce(lambda x, y: x + y, map(lambda x, y: rnl[x][y], range(4), str(n).zfill(4))) if -1 < n < 5000 else None</lang>
Or, defining roman in terms of mapAccumL:
<lang python>Encoding Roman Numerals
from functools import reduce from itertools import chain
- romanFromInt :: Int -> String
def romanFromInt(n):
A string of Roman numerals encoding an integer.
def go(a, ms):
m, s = ms
q, r = divmod(a, m)
return (r, s * q)
return concat(snd(mapAccumL(go)(n)(
zip([
1000, 900, 500, 400, 100, 90, 50,
40, 10, 9, 5, 4, 1
], [
'M', 'CM', 'D', 'CD', 'C', 'XC', 'L',
'XL', 'X', 'IX', 'V', 'IV', 'I'
])
)))
- ------------------------- TEST -------------------------
- main :: IO ()
def main():
Sample of years
for s in [
romanFromInt(x) for x in [
1666, 1990, 2008, 2016, 2018, 2020
]
]:
print(s)
- ------------------ GENERIC FUNCTIONS -------------------
- concat :: a -> [a]
- concat :: [String] -> String
def concat(xxs):
The concatenation of all the elements in a list.
xs = list(chain.from_iterable(xxs))
unit = if isinstance(xs, str) else []
return unit if not xs else (
.join(xs) if isinstance(xs[0], str) else xs
)
- mapAccumL :: (acc -> x -> (acc, y)) -> acc -> [x] -> (acc, [y])
def mapAccumL(f):
A tuple of an accumulation and a list derived by a
combined map and fold,
with accumulation from left to right.
def go(a, x):
tpl = f(a[0], x)
return (tpl[0], a[1] + [tpl[1]])
return lambda acc: lambda xs: (
reduce(go, xs, (acc, []))
)
- snd :: (a, b) -> b
def snd(tpl):
Second component of a tuple. return tpl[1]
- MAIN ---
if __name__ == '__main__':
main()</lang>
- Output:
MDCLXVI MCMXC MMVIII MMXVI MMXVIII MMXX
QBasic
<lang QBasic>DIM SHARED arabic(0 TO 12) DIM SHARED roman$(0 TO 12)
FUNCTION toRoman$ (value)
LET result$ = ""
FOR i = 0 TO 12
DO WHILE value >= arabic(i)
LET result$ = result$ + roman$(i)
LET value = value - arabic(i)
LOOP
NEXT i
toRoman$ = result$
END FUNCTION
FOR i = 0 TO 12
READ arabic(i), roman$(i)
NEXT i
DATA 1000, "M", 900, "CM", 500, "D", 400, "CD", 100, "C", 90, "XC" DATA 50, "L", 40, "XL", 10, "X", 9, "IX", 5, "V", 4, "IV", 1, "I"
'Testing PRINT "2009 = "; toRoman$(2009) PRINT "1666 = "; toRoman$(1666) PRINT "3888 = "; toRoman$(3888)</lang>
Quackery
Pasting epitomised.
<lang Quackery> [ $ ""
swap 1000 /mod $ "M" rot of rot swap join swap
dup 900 < not if [ 900 - dip [ $ "CM" join ] ]
dup 500 < not if [ 500 - dip [ $ "D" join ] ]
dup 400 < not if [ 400 - dip [ $ "CD" join ] ]
100 /mod $ "C" rot of rot swap join swap
dup 90 < not if [ 90 - dip [ $ "XC" join ] ]
dup 50 < not if [ 50 - dip [ $ "L" join ] ]
dup 40 < not if [ 40 - dip [ $ "XL" join ] ]
10 /mod $ "X" rot of rot swap join swap
dup 9 < not if [ 9 - dip [ $ "IX" join ] ]
dup 5 < not if [ 5 - dip [ $ "V" join ] ]
dup 4 < not if [ 4 - dip [ $ "IV" join ] ]
$ "I" swap of join ]
is ->roman ( n --> $ )
1990 dup echo say " = " ->roman echo$ cr 2008 dup echo say " = " ->roman echo$ cr 1666 dup echo say " = " ->roman echo$ cr</lang>
- Output:
1990 = MCMXC 2008 = MMVIII 1666 = MDCLXVI
R
R has a built-in function, as.roman, for conversion to Roman numerals. The implementation details are found in utils:::.numeric2roman (see previous link), and utils:::.roman2numeric, for conversion back to Arabic decimals.
<lang R>as.roman(1666) # MDCLXVI</lang>
Since the object as.roman creates is just an integer vector with a class, you can do arithmetic with Roman numerals:
<lang R>as.roman(1666) + 334 # MM</lang>
Racket
Straight recursion: <lang Racket>#lang racket (define (encode/roman number)
(cond ((>= number 1000) (string-append "M" (encode/roman (- number 1000))))
((>= number 900) (string-append "CM" (encode/roman (- number 900))))
((>= number 500) (string-append "D" (encode/roman (- number 500))))
((>= number 400) (string-append "CD" (encode/roman (- number 400))))
((>= number 100) (string-append "C" (encode/roman (- number 100))))
((>= number 90) (string-append "XC" (encode/roman (- number 90))))
((>= number 50) (string-append "L" (encode/roman (- number 50))))
((>= number 40) (string-append "XL" (encode/roman (- number 40))))
((>= number 10) (string-append "X" (encode/roman (- number 10))))
((>= number 9) (string-append "IX" (encode/roman (- number 9))))
((>= number 5) (string-append "V" (encode/roman (- number 5))))
((>= number 4) (string-append "IV" (encode/roman (- number 4))))
((>= number 1) (string-append "I" (encode/roman (- number 1))))
(else "")))</lang>
Using for/fold and quotient/remainder to remove repetition: <lang Racket>#lang racket (define (number->list n)
(for/fold ([result null])
([decimal '(1000 900 500 400 100 90 50 40 10 9 5 4 1)]
[roman '(M CM D CD C XC L XL X IX V IV I)])
#:break (= n 0)
(let-values ([(q r) (quotient/remainder n decimal)])
(set! n r)
(append result (make-list q roman)))))
(define (encode/roman number)
(string-join (map symbol->string (number->list number)) ""))
(for ([n '(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 25 30 40
50 60 69 70 80 90 99 100 200 300 400 500 600 666 700 800 900
1000 1009 1444 1666 1945 1997 1999 2000 2008 2010 2011 2500
3000 3999)])
(printf "~a ~a\n" n (encode/roman n)))</lang>
Raku
(formerly Perl 6)
<lang perl6>my %symbols =
1 => "I", 5 => "V", 10 => "X", 50 => "L", 100 => "C", 500 => "D", 1_000 => "M";
my @subtractors =
1_000, 100, 500, 100, 100, 10, 50, 10, 10, 1, 5, 1, 1, 0;
multi sub roman (0) { } multi sub roman (Int $n) {
for @subtractors -> $cut, $minus {
$n >= $cut
and return %symbols{$cut} ~ roman($n - $cut);
$n >= $cut - $minus
and return %symbols{$minus} ~ roman($n + $minus);
}
}
- Sample usage
for 1 .. 2_010 -> $x {
say roman($x);
}</lang>
Red
Straight iterative solution: <lang Red> table: [1000 M 900 CM 500 D 400 CD 100 C 90 XC 50 L 40 XL 10 X 5 V 4 IV 1 I]
to-Roman: function [n [integer!] return: [string!]][
out: copy "" foreach [a r] table [while [n >= a][append out r n: n - a]] out
]
foreach number [40 33 1888 2016][print [number ":" to-Roman number]] </lang> Straight recursive solution: <lang Red> table: [1000 M 900 CM 500 D 400 CD 100 C 90 XC 50 L 40 XL 10 X 5 V 4 IV 1 I]
to-Roman: func [n [integer!] return: [string!]][
case [
tail? table [table: head table copy ""]
table/1 > n [table: skip table 2 to-Roman n]
'else [append copy form table/2 to-Roman n - table/1]
]
]
foreach number [40 33 1888 2016][print [number ":" to-Roman number]] </lang> This solution builds, using metaprogramming, a `case` table, that relies on recursion to convert every digit.
<lang Red> to-Roman: function [n [integer!]] reduce [
'case collect [
foreach [a r] [1000 M 900 CM 500 D 400 CD 100 C 90 XC 50 L 40 XL 10 X 9 IX 5 V 4 IV 1 I][
keep compose/deep [n >= (a) [append copy (form r) any [to-Roman n - (a) copy ""]]]
]
]
]
foreach number [40 33 1888 2016][print [number ":" to-Roman number]] </lang>
Retro
This is a port of the Forth code; but returns a string rather than displaying the roman numerals. It only handles numbers between 1 and 3999.
<lang Retro>
- vector ( ...n"- )
here [ &, times ] dip : .data ` swap ` + ` @ ` do ` ; ;
- .I dup @ ^buffer'add ;
- .V dup 1 + @ ^buffer'add ;
- .X dup 2 + @ ^buffer'add ;
[ .I .X drop ] [ .V .I .I .I drop ] [ .V .I .I drop ] [ .V .I drop ] [ .V drop ] [ .I .V drop ] [ .I .I .I drop ] [ .I .I drop ] [ .I drop ] &drop 10 vector .digit
- record ( an- )
10 /mod dup [ [ over 2 + ] dip record ] &drop if .digit ;
- toRoman ( n-a )
here ^buffer'set dup 1 3999 within 0 = [ "EX LIMITO!\n" ] [ "IVXLCDM" swap record here ] if ;
</lang>
REXX
version 1
<lang rexx>roman: procedure arg number
/* handle only 1 to 3999, else return ? */ if number >= 4000 | number <= 0 then return "?"
romans = " M CM D CD C XC L XL X IX V IV I" arabic = "1000 900 500 400 100 90 50 40 10 9 5 4 1"
result = "" do i = 1 to words(romans)
do while number >= word(arabic,i) result = result || word(romans,i) number = number - word(arabic,i) end
end return result</lang>
version 2
This version of a REXX program allows almost any non-negative decimal integer.
Most people think that the Romans had no word for "zero". The Roman numeral system has no need for a
zero placeholder, so there was no name for it (just as we have no name for a "¶" in the middle of our
numbers ─── as we don't have that possibility). However, the Romans did have a name for zero (or nothing).
In fact the Romans had several names for zero (see the REXX code), as does modern English. In American
English, many words can be used for 0: zero, nothing, naught, bupkis, zilch, goose-egg, nebbish, squat, nil,
crapola, what-Patty-shot-at, nineteen (only in cribbage), love (in tennis), etc.
Also, this REXX version supports large numbers (with parentheses and deep parentheses).
(This REXX code was ripped out of my general routine that also supported versions for Attic, ancient Roman,
and modern Roman numerals.)
The general REXX code is bulkier than most at it deals with any non-negative decimal number, and more
boilerplate code is in the general REXX code to handle the above versions.
<lang rexx>/*REXX program converts (Arabic) non─negative decimal integers (≥0) ───► Roman numerals.*/
numeric digits 10000 /*decimal digs can be higher if wanted.*/
parse arg # /*obtain optional integers from the CL.*/
@er= "argument isn't a non-negative integer: " /*literal used when issuing error msg. */
if #= then /*Nothing specified? Then generate #s.*/
do
do j= 0 by 11 to 111; #=# j; end
#=# 49; do k=88 by 100 to 1200; #=# k; end
#=# 1000 2000 3000 4000 5000 6000; do m=88 by 200 to 1200; #=# m; end
#=# 1304 1405 1506 1607 1708 1809 1910 2011; do p= 4 to 50; #=# 10**p; end
end /*finished with generation of numbers. */
do i=1 for words(#); x=word(#, i) /*convert each of the numbers───►Roman.*/ if \datatype(x, 'W') | x<0 then say "***error***" @er x /*¬ whole #? negative?*/ say right(x, 55) dec2rom(x) end /*i*/
exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ dec2rom: procedure; parse arg n,# /*obtain the number, assign # to a null*/
n=space(translate(n/1, , ','), 0) /*remove commas from normalized integer*/
nulla= 'ZEPHIRUM NULLAE NULLA NIHIL' /*Roman words for "nothing" or "none". */
if n==0 then return word(nulla, 1) /*return a Roman word for "zero". */
maxnp=(length(n)-1)%3 /*find max(+1) # of parenthesis to use.*/
highPos=(maxnp+1)*3 /*highest position of number. */
nn=reverse( right(n, highPos, 0) ) /*digits for Arabic──►Roman conversion.*/
do j=highPos to 1 by -3
_=substr(nn, j, 1); select /*════════════════════hundreds.*/
when _==9 then hx='CM'
when _>=5 then hx='D'copies("C", _-5)
when _==4 then hx='CD'
otherwise hx= copies('C', _)
end /*select hundreds*/
_=substr(nn, j-1, 1); select /*════════════════════════tens.*/
when _==9 then tx='XC'
when _>=5 then tx='L'copies("X", _-5)
when _==4 then tx='XL'
otherwise tx= copies('X', _)
end /*select tens*/
_=substr(nn, j-2, 1); select /*═══════════════════════units.*/
when _==9 then ux='IX'
when _>=5 then ux='V'copies("I", _-5)
when _==4 then ux='IV'
otherwise ux= copies('I', _)
end /*select units*/
$=hx || tx || ux
if $\== then #=# || copies("(", (j-1)%3)$ ||copies(')', (j-1)%3)
end /*j*/
if pos('(I',#)\==0 then do i=1 for 4 /*special case: M,MM,MMM,MMMM.*/
if i==4 then _ = '(IV)'
else _ = '('copies("I", i)')'
if pos(_, #)\==0 then #=changestr(_, #, copies('M', i))
end /*i*/
return #</lang>
Some older REXXes don't have a changestr BIF, so one is included here ──► CHANGESTR.REX.
output when using the default (internal) input):
0 ZEPHIRUM
11 XI
22 XXII
33 XXXIII
44 XLIV
55 LV
66 LXVI
77 LXXVII
88 LXXXVIII
99 XCIX
110 CX
49 XLIX
88 LXXXVIII
188 CLXXXVIII
288 CCLXXXVIII
388 CCCLXXXVIII
488 CDLXXXVIII
588 DLXXXVIII
688 DCLXXXVIII
788 DCCLXXXVIII
888 DCCCLXXXVIII
988 CMLXXXVIII
1088 MLXXXVIII
1188 MCLXXXVIII
1000 M
2000 MM
3000 MMM
4000 MMMM
5000 (V)
6000 (VI)
88 LXXXVIII
288 CCLXXXVIII
488 CDLXXXVIII
688 DCLXXXVIII
888 DCCCLXXXVIII
1088 MLXXXVIII
1304 MCCCIV
1405 MCDV
1506 MDVI
1607 MDCVII
1708 MDCCVIII
1809 MDCCCIX
1910 MCMX
2011 MMXI
10000 (X)
100000 (C)
1000000 (M)
10000000 ((X))
100000000 ((C))
1000000000 ((M))
10000000000 (((X)))
100000000000 (((C)))
1000000000000 (((M)))
10000000000000 ((((X))))
100000000000000 ((((C))))
1000000000000000 ((((M))))
10000000000000000 (((((X)))))
100000000000000000 (((((C)))))
1000000000000000000 (((((M)))))
10000000000000000000 ((((((X))))))
100000000000000000000 ((((((C))))))
1000000000000000000000 ((((((M))))))
10000000000000000000000 (((((((X)))))))
100000000000000000000000 (((((((C)))))))
1000000000000000000000000 (((((((M)))))))
10000000000000000000000000 ((((((((X))))))))
100000000000000000000000000 ((((((((C))))))))
1000000000000000000000000000 ((((((((M))))))))
10000000000000000000000000000 (((((((((X)))))))))
100000000000000000000000000000 (((((((((C)))))))))
1000000000000000000000000000000 (((((((((M)))))))))
10000000000000000000000000000000 ((((((((((X))))))))))
100000000000000000000000000000000 ((((((((((C))))))))))
1000000000000000000000000000000000 ((((((((((M))))))))))
10000000000000000000000000000000000 (((((((((((X)))))))))))
100000000000000000000000000000000000 (((((((((((C)))))))))))
1000000000000000000000000000000000000 (((((((((((M)))))))))))
10000000000000000000000000000000000000 ((((((((((((X))))))))))))
100000000000000000000000000000000000000 ((((((((((((C))))))))))))
1000000000000000000000000000000000000000 ((((((((((((M))))))))))))
10000000000000000000000000000000000000000 (((((((((((((X)))))))))))))
100000000000000000000000000000000000000000 (((((((((((((C)))))))))))))
1000000000000000000000000000000000000000000 (((((((((((((M)))))))))))))
10000000000000000000000000000000000000000000 ((((((((((((((X))))))))))))))
100000000000000000000000000000000000000000000 ((((((((((((((C))))))))))))))
1000000000000000000000000000000000000000000000 ((((((((((((((M))))))))))))))
10000000000000000000000000000000000000000000000 (((((((((((((((X)))))))))))))))
100000000000000000000000000000000000000000000000 (((((((((((((((C)))))))))))))))
1000000000000000000000000000000000000000000000000 (((((((((((((((M)))))))))))))))
10000000000000000000000000000000000000000000000000 ((((((((((((((((X))))))))))))))))
100000000000000000000000000000000000000000000000000 ((((((((((((((((C))))))))))))))))
Ring
<lang ring> arabic = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1] roman = ["M", "CM", "D", "CD", "C" ,"XC", "L", "XL" ,"X", "IX", "V", "IV", "I"]
see "2009 = " + toRoman(2009) + nl see "1666 = " + toRoman(1666) + nl see "3888 = " + toRoman(3888) + nl
func toRoman val
result = ""
for i = 1 to 13
while val >= arabic[i]
result = result + roman[i]
val = val - arabic[i]
end
next
return result
</lang>
Ruby
Roman numeral generation was used as an example for demonstrating Test Driven Development in Ruby. The solution came to be: <lang ruby>Symbols = { 1=>'I', 5=>'V', 10=>'X', 50=>'L', 100=>'C', 500=>'D', 1000=>'M' } Subtractors = [ [1000, 100], [500, 100], [100, 10], [50, 10], [10, 1], [5, 1], [1, 0] ]
def roman(num)
return Symbols[num] if Symbols.has_key?(num) Subtractors.each do |cutPoint, subtractor| return roman(cutPoint) + roman(num - cutPoint) if num > cutPoint return roman(subtractor) + roman(num + subtractor) if num >= cutPoint - subtractor and num < cutPoint end
end
[1990, 2008, 1666].each do |i|
puts "%4d => %s" % [i, roman(i)]
end</lang>
- Output:
1990 => MCMXC 2008 => MMVIII 1666 => MDCLXVI
Another shorter version if we don't consider calculating the substractors:
<lang ruby> Symbols = [ [1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I'] ]
def arabic_to_roman(arabic)
return if arabic.zero?
Symbols.each { |arabic_rep, roman_rep| return roman_rep + arabic_to_roman(arabic - arabic_rep) if arabic >= arabic_rep }
end </lang>
Yet another way to solve it in terms of reduce
<lang ruby> Symbols = [ [1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I'] ]
def to_roman(num)
Symbols.reduce "" do |memo, (divisor, letter)|
div, num = num.divmod(divisor)
memo + letter * div
end
end </lang>
Run BASIC
<lang runbasic>[loop] input "Input value:";val$ print roman$(val$) goto [loop]
' ------------------------------ ' Roman numerals ' ------------------------------ FUNCTION roman$(val$) a2r$ = "M:1000,CM:900,D:500,CD:400,C:100,XC:90,L:50,XL:40,X:10,IX:9,V:5,IV:4,I:1" v = val(val$) for i = 1 to 13
r$ = word$(a2r$,i,",") a = val(word$(r$,2,":")) while v >= a roman$ = roman$ + word$(r$,1,":") v = v - a wend
next i END FUNCTION</lang>
Rust
<lang rust>struct RomanNumeral {
symbol: &'static str, value: u32
}
const NUMERALS: [RomanNumeral; 13] = [
RomanNumeral {symbol: "M", value: 1000},
RomanNumeral {symbol: "CM", value: 900},
RomanNumeral {symbol: "D", value: 500},
RomanNumeral {symbol: "CD", value: 400},
RomanNumeral {symbol: "C", value: 100},
RomanNumeral {symbol: "XC", value: 90},
RomanNumeral {symbol: "L", value: 50},
RomanNumeral {symbol: "XL", value: 40},
RomanNumeral {symbol: "X", value: 10},
RomanNumeral {symbol: "IX", value: 9},
RomanNumeral {symbol: "V", value: 5},
RomanNumeral {symbol: "IV", value: 4},
RomanNumeral {symbol: "I", value: 1}
];
fn to_roman(mut number: u32) -> String {
let mut min_numeral = String::new();
for numeral in NUMERALS.iter() {
while numeral.value <= number {
min_numeral = min_numeral + numeral.symbol;
number -= numeral.value;
}
}
min_numeral
}
fn main() {
let nums = [2014, 1999, 25, 1666, 3888];
for &n in nums.iter() {
// 4 is minimum printing width, for alignment
println!("{:2$} = {}", n, to_roman(n), 4);
}
}</lang>
- Output:
2014 = MMXIV 1999 = MCMXCIX 25 = XXV 1666 = MDCLXVI 3888 = MMMDCCCLXXXVIII
Scala
<lang scala>val romanDigits = Map(
1 -> "I", 5 -> "V", 10 -> "X", 50 -> "L", 100 -> "C", 500 -> "D", 1000 -> "M", 4 -> "IV", 9 -> "IX", 40 -> "XL", 90 -> "XC", 400 -> "CD", 900 -> "CM")
val romanDigitsKeys = romanDigits.keysIterator.toList sortBy (x => -x) def toRoman(n: Int): String = romanDigitsKeys find (_ >= n) match {
case Some(key) => romanDigits(key) + toRoman(n - key) case None => ""
}</lang>
- Output:
scala> List(1990, 2008, 1666) map toRoman res55: List[String] = List(MCMXC, MMVIII, MDCLXVI)
Using foldLeft
<lang Scala>def toRoman( v:Int ) : String = {
val romanNumerals = List(1000->"M",900->"CM",500->"D",400->"CD",100->"C",90->"XC",
50->"L",40->"XL",10->"X",9->"IX",5->"V",4->"IV",1->"I")
var n = v
romanNumerals.foldLeft(""){(s,t) => {val c = n/t._1; n = n-t._1*c; s + (t._2 * c) } }
}
// A small test def test( arabic:Int ) = println( arabic + " => " + toRoman( arabic ) )
test(1990) test(2008) test(1666)</lang>
Different code-style
<lang Scala>def toRoman(num: Int): String = {
case class RomanUnit(value: Int, token: String) val romanNumerals = List( RomanUnit(1000, "M"), RomanUnit(900, "CM"), RomanUnit(500, "D"), RomanUnit(400, "CD"), RomanUnit(100, "C"), RomanUnit(90, "XC"), RomanUnit(50, "L"), RomanUnit(40, "XL"), RomanUnit(10, "X"), RomanUnit(9, "IX"), RomanUnit(5, "V"), RomanUnit(4, "IV"), RomanUnit(1, "I"))
var remainingNumber = num
romanNumerals.foldLeft("") { (outputStr, romanUnit) =>
{
val times = remainingNumber / romanUnit.value
remainingNumber -= romanUnit.value * times
outputStr + (romanUnit.token * times)
}
}
}</lang>
- Output:
1990 => MCMXC 2008 => MMVIII 1666 => MDCLXVI
Scheme
This uses format directives supported in Chez Scheme since v6.9b; YMMV.
<lang scheme>(define (to-roman n)
(format "~@r" n))</lang>
This is a general example using Chicken Scheme. <lang scheme>(define roman-decimal
'(("M" . 1000)
("CM" . 900)
("D" . 500)
("CD" . 400)
("C" . 100)
("XC" . 90)
("L" . 50)
("XL" . 40)
("X" . 10)
("IX" . 9)
("V" . 5)
("IV" . 4)
("I" . 1)))
(define (to-roman value)
(apply string-append
(let loop ((v value)
(decode roman-decimal))
(let ((r (caar decode))
(d (cdar decode)))
(cond
((= v 0) '())
((>= v d) (cons r (loop (- v d) decode)))
(else (loop v (cdr decode))))))))
(let loop ((n '(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 25 30 40
50 60 69 70 80 90 99 100 200 300 400 500 600 666 700 800 900
1000 1009 1444 1666 1945 1997 1999 2000 2008 2010 2011 2500
3000 3999)))
(unless (null? n)
(printf "~a ~a\n" (car n) (to-roman (car n)))
(loop (cdr n))))
</lang>
Seed7
The following program writes the numbers between 1 and 3999 as roman numerals. The wrinum.s7i library contains the function str(ROMAN,), which writes a roman numeral to a string.
<lang seed7>$ include "seed7_05.s7i";
include "stdio.s7i"; include "wrinum.s7i";
const proc: main is func
local
var integer: number is 0;
begin
for number range 1 to 3999 do
writeln(str(ROMAN, number));
end for;
end func;</lang>
Original source [1].
SenseTalk
<lang sensetalk>function RomanNumeralsEncode number put [ (1, "I"), (4, "IV"), (5, "V"), (9, "IX"), (10, "X"), (40, "XL"), (50, "L"), (90, "XC"), (100, "C"), (400, "CD"), (500, "D"), (900, "CM"), (1000, "M") ] into values
repeat for index = each item of (the number of items in values)..1
put item index of values into pair
repeat while number is greater than or equal to the first item of pair
put the second item of pair after numerals
subtract the first item of pair from number
end repeat
end repeat
return numerals
end RomanNumeralsEncode</lang>
<lang sensetalk>repeat for each item in [ 1990, 2008, 1666 ] put RomanNumeralsEncode(it) end repeat</lang>
- Output:
MCMXC MMVIII MDCLXVI
SETL
<lang ada>examples := [2008, 1666, 1990];
for example in examples loop
print( roman_numeral(example) );
end loop;
proc roman_numeral( n );
R := [[1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I']];
roman := ;
for numeral in R loop
while n >= numeral(1) loop
n := n - numeral(1);
roman := roman + numeral(2);
end loop;
end loop;
return roman;
end;</lang>
- Output:
MMVIII MDCLXVI MCMXC
Shen
<lang shen> (define encodeGlyphs
ACC 0 _ -> ACC ACC N [Glyph Value | Rest] -> (encodeGlyphs (@s ACC Glyph) (- N Value) [Glyph Value | Rest]) where (>= N Value) ACC N [Glyph Value | Rest] -> (encodeGlyphs ACC N Rest)
)
(define encodeRoman
N -> (encodeGlyphs "" N ["M" 1000 "CM" 900 "D" 500 "CD" 400 "C" 100 "XC" 90 "L" 50 "XL" 40 "X" 10 "IX" 9 "V" 5 "IV" 4 "I" 1])
) </lang>
- Output:
(4-) (encodeRoman 1990) "MCMXC" (5-) (encodeRoman 2008) "MMVIII" (6-) (encodeRoman 1666) "MDCLXVI"
Sidef
<lang ruby>func arabic2roman(num, roman=) {
static lookup = [
:M:1000, :CM:900, :D:500,
:CD:400, :C:100, :XC:90,
:L:50, :XL:40, :X:10,
:IX:9, :V:5, :IV:4,
:I:1
];
lookup.each { |pair|
while (num >= pair.second) {
roman += pair.first;
num -= pair.second;
}
}
return roman;
} say("1990 in roman is " + arabic2roman(1990)); say("2008 in roman is " + arabic2roman(2008)); say("1666 in roman is " + arabic2roman(1666));</lang>
- Output:
1990 in roman is MCMXC 2008 in roman is MMVIII 1666 in roman is MDCLXVI
Simula
<lang simula>BEGIN
TEXT PROCEDURE TOROMAN(N); INTEGER N;
BEGIN
PROCEDURE P(WEIGHT,LIT); INTEGER WEIGHT; TEXT LIT;
BEGIN
WHILE N >= WEIGHT DO
BEGIN
T :- T & LIT;
N := N - WEIGHT;
END WHILE;
END P;
TEXT T; T :- NOTEXT;
P( 1000, "M" );
P( 900, "CM" );
P( 500, "D" );
P( 400, "CD" );
P( 100, "C" );
P( 90, "XC" );
P( 50, "L" );
P( 40, "XL" );
P( 10, "X" );
P( 9, "IX" );
P( 5, "V" );
P( 4, "IV" );
P( 1, "I" );
TOROMAN :- T;
END TOROMAN;
INTEGER Y;
FOR Y := 1990, 2008, 1666 DO
BEGIN
OUTTEXT("YEAR ");
OUTINT(Y, 4);
OUTTEXT(" => ");
OUTTEXT(TOROMAN(Y));
OUTIMAGE;
END FOR;
END PROGRAM; </lang>
- Output:
YEAR 1990 => MCMXC YEAR 2008 => MMVIII YEAR 1666 => MDCLXVI
Smalltalk
in ST/X, integers already know how to print themselves as roman number: <lang smalltalk>2013 printRomanOn:Stdout naive:false</lang>
- Output:
MMXIII
the implementation is: <lang smalltalk> printRomanOn:aStream naive:naive
"print the receiver as roman number to the argument, aStream.
The naive argument controls if the conversion is
correct (i.e. subtracting prefix notation for 4,9,40,90, etc.),
or naive (i.e. print 4 as IIII and 9 as VIIII); also called simple.
The naive version is often used for page numbers in documents."
|restValue spec|
restValue := self. restValue > 0 ifFalse:[self error:'negative roman'].
naive ifTrue:[
spec := #(
" value string repeat "
1000 'M' true
500 'D' false
100 'C' true
50 'L' false
10 'X' true
5 'V' false
1 'I' true
).
] ifFalse:[
spec := #(
" value string repeat "
1000 'M' true
900 'CM' false
500 'D' false
400 'CD' false
100 'C' true
90 'XC' false
50 'L' false
40 'XL' false
10 'X' true
9 'IX' false
5 'V' false
4 'IV' false
1 'I' true
).
].
spec
inGroupsOf:3
do:[:rValue :rString :repeatFlag |
[
(restValue >= rValue) ifTrue:[
aStream nextPutAll:rString.
restValue := restValue - rValue.
].
] doWhile:[ repeatFlag and:[ restValue >= rValue] ].
].
</lang>
SNOBOL4
Adapted from Catspaw SNOBOL Tutorial, Chapter 6
<lang snobol4>
- ROMAN(N) - Convert integer N to Roman numeral form.
- N must be positive and less than 4000.
- An asterisk appears in the result if N >= 4000.
- The function fails if N is not an integer.
DEFINE('ROMAN(N)UNITS') :(ROMAN_END)
- Get rightmost digit to UNITS and remove it from N.
- Return null result if argument is null.
ROMAN N RPOS(1) LEN(1) . UNITS = :F(RETURN)
- Search for digit, replace with its Roman form.
- Return failing if not a digit.
'0,1I,2II,3III,4IV,5V,6VI,7VII,8VIII,9IX,' UNITS + BREAK(',') . UNITS :F(FRETURN)
- Convert rest of N and multiply by 10. Propagate a
- failure return from recursive call back to caller.
ROMAN = REPLACE(ROMAN(N), 'IVXLCDM', 'XLCDM**') + UNITS :S(RETURN) F(FRETURN) ROMAN_END
- Testing
OUTPUT = "1999 = " ROMAN(1999) OUTPUT = " 24 = " ROMAN(24) OUTPUT = " 944 = " ROMAN(944)
END</lang>
- Output:
1999 = MCMXCIX 24 = XXIV 944 = CMXLIV
Here's a non-recursive version, and a Roman-to-Arabic converter to boot.
<lang SNOBOL4>* # Arabic to Roman
define('roman(n)s,ch,val,str') :(roman_end)
roman roman = ge(n,4000) n :s(return)
s = 'M1000 CM900 D500 CD400 C100 XC90 L50 XL40 X10 IX9 V5 IV4 I1 '
rom1 s span(&ucase) . ch break(' ') . val span(' ') = :f(rom2)
str = str dupl(ch,(n / val))
n = remdr(n,val) :(rom1)
rom2 roman = str :(return) roman_end
- # Roman to Arabic
define('arabic(n)s,ch,val,sum,x') :(arabic_end)
arabic s = 'M1000 D500 C100 L50 X10 V5 I1 '
n = reverse(n)
arab1 n len(1) . ch = :f(arab2)
s ch break(' ') . val
val = lt(val,x) (-1 * val)
sum = sum + val; x = val :(arab1)
arab2 arabic = sum :(return) arabic_end
- # Test and display
tstr = '2010 1999 1492 1066 476 '
tloop tstr break(' ') . year span(' ') = :f(out)
r = roman(year)
rstr = rstr year '=' r ' '
astr = astr r '=' arabic(r) ' ' :(tloop)
out output = rstr; output = astr end</lang>
- Output:
2010=MMX 1999=MCMXCIX 1492=MCDXCII 1066=MLXVI 476=CDLXXVI MMX=2010 MCMXCIX=1999 MCDXCII=1492 MLXVI=1066 CDLXXVI=476
SPL
<lang spl>a2r(a)=
r = ""
n = [["M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"],[1000,900,500,400,100,90,50,40,10,9,5,4,1]]
> i, 1..13
> a!<n[i,2]
r += n[i,1]
a -= n[i,2]
<
<
<= r
.
t = [1990,2008,1666] > i, 1..#.size(t,1)
#.output(t[i]," = ",a2r(t[i]))
<</lang>
- Output:
1990 = MCMXC 2008 = MMVIII 1666 = MDCLXVI
SQL
<lang SQL> -- -- This only works under Oracle and has the limitation of 1 to 3999
SQL> select to_char(1666, 'RN') urcoman, to_char(1666, 'rn') lcroman from dual;
URCOMAN LCROMAN
---------------
MDCLXVI mdclxvi
</lang>
Swift
<lang swift>func ator(var n: Int) -> String {
var result = ""
for (value, letter) in
[( 1000, "M"),
( 900, "CM"),
( 500, "D"),
( 400, "CD"),
( 100, "C"),
( 90, "XC"),
( 50, "L"),
( 40, "XL"),
( 10, "X"),
( 9, "IX"),
( 5, "V"),
( 4, "IV"),
( 1, "I")]
{
while n >= value {
result += letter
n -= value
}
}
return result
}</lang> Sample call:
<lang swift>println(ator(1666)) // MDCLXVI</lang>
<lang swift>print(ator(1666)) // MDCLXVI</lang>
- Output:
MDCLXVI
Tailspin
<lang tailspin> def digits: [(M:1000"1"), (CM:900"1"), (D:500"1"), (CD:400"1"), (C:100"1"), (XC:90"1"), (L:50"1"), (XL:40"1"), (X:10"1"), (IX:9"1"), (V:5"1"), (IV:4"1"), (I:1"1")]; templates encodeRoman
@: 1; '$ -> #;' ! when <$digits($@)::value..> do $digits($@)::key ! $ - $digits($@)::value -> # when <1..> do @:$@ + 1; $ -> #
end encodeRoman
1990 -> encodeRoman -> !OUT::write ' ' -> !OUT::write 2008 -> encodeRoman -> !OUT::write ' ' -> !OUT::write 1666 -> encodeRoman -> !OUT::write </lang>
- Output:
MCMXC MMVIII MDCLXVI
Tcl
<lang tcl>proc to_roman {i} {
set map {1000 M 900 CM 500 D 400 CD 100 C 90 XC 50 L 40 XL 10 X 9 IX 5 V 4 IV 1 I}
foreach {value roman} $map {
while {$i >= $value} {
append res $roman
incr i -$value
}
}
return $res
}</lang>
TI-83 BASIC
<lang ti83b>PROGRAM:DEC2ROM
- "="→Str1
- Lbl ST
- ClrHome
- Disp "NUMBER TO"
- Disp "CONVERT:"
- Input A
- If fPart(A) or A≠abs(A)
- Then
- Goto PI
- End
- A→B
- While B≥1000
- Str1+"M"→Str1
- B-1000→B
- End
- If B≥900
- Then
- Str1+"CM"→Str1
- B-900→B
- End
- If B≥500
- Then
- Str1+"D"→Str1
- B-500→B
- End
- If B≥400
- Then
- Str1+"CD"?Str1
- B-400→B
- End
- While B≥100
- Str1+"C"→Str1
- B-100→B
- End
- If B≥90
- Then
- Str1+"XC"→Str1
- B-90→B
- End
- If B≥50
- Then
- Str1+"L"→Str1
- B-50→B
- End
- If B≥40
- Then
- Str1+"XL"→Str1
- B-40→B
- End
- While B≥10
- Str1+"X"→Str1
- B-10→B
- End
- If B≥9
- Then
- Str1+"IX"→Str1
- B-9→B
- End
- If B≥5
- Then
- Str1+"V"→Str1
- B-5→B
- End
- If B≥4
- Then
- Str1+"IV"→Str1
- B-4→B
- End
- While B>0
- Str1+"I"→Str1
- B-1→B
- End
- ClrHome
- Disp A
- Disp Str1
- Stop
- Lbl PI
- ClrHome
- Disp "THE NUMBER MUST"
- Disp "BE A POSITIVE"
- Disp "INTEGER."
- Pause
- Goto ST
</lang>
True BASIC
<lang qbasic>OPTION BASE 0 DIM arabic(12), roman$(12)
FOR i = 0 to 12
READ arabic(i), roman$(i)
NEXT i
DATA 1000, "M", 900, "CM", 500, "D", 400, "CD", 100, "C", 90, "XC" DATA 50, "L", 40, "XL", 10, "X", 9, "IX", 5, "V", 4, "IV", 1, "I"
FUNCTION toRoman$(value)
LET result$ = ""
FOR i = 0 TO 12
DO WHILE value >= arabic(i)
LET result$ = result$ & roman$(i)
LET value = value - arabic(i)
LOOP
NEXT i
LET toRoman$ = result$
END FUNCTION
!Testing PRINT "2009 = "; toRoman$(2009) PRINT "1666 = "; toRoman$(1666) PRINT "3888 = "; toRoman$(3888) END</lang>
TUSCRIPT
<lang tuscript> $$ MODE TUSCRIPT LOOP arab_number="1990'2008'1666" roman_number = ENCODE (arab_number,ROMAN) PRINT "Arabic number ",arab_number, " equals ", roman_number ENDLOOP </lang>
- Output:
Arabic number 1990 equals MCMXC Arabic number 2008 equals MMVIII Arabic number 1666 equals MDCLXVI
TypeScript
Weights and symbols in tuples. <lang javascript> // Roman numerals/Encode
const weightsSymbols: [number, string][] =
[[1000, 'M'], [900, 'CM'], [500, 'D'], [400, 'CD'], [100, 'C'], [90, 'XC'], [50, 'L'], [40, 'XL'], [10, 'X'], [9, 'IX'], [5, 'V'], [4, 'IV'], [1, 'I']];
// 3888 or MMMDCCCLXXXVIII (15 chars) is the longest string properly encoded // with these symbols.
function toRoman(n: number): string {
var roman = ""; // Result
for (i = 0; i <= 12 && n > 0; i++) {
var w = weightsSymbols[i][0];
while (n >= w) {
roman += weightsSymbols[i][1];
n -= w;
}
}
return roman;
}
console.log(toRoman(1990)); // MCMXC console.log(toRoman(2022)); // MMXXII console.log(toRoman(3888)); // MMMDCCCLXXXVIII </lang>
- Output:
MCMXC MMXXII MMMDCCCLXXXVIII
uBasic/4tH
<lang>Push 1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000
' Initialize array
For i = 12 To 0 Step -1
@(i) = Pop()
Next
' Calculate and print numbers
Print 1999, : Proc _FNroman (1999) Print 2014, : Proc _FNroman (2014) Print 1666, : Proc _FNroman (1666) Print 3888, : Proc _FNroman (3888)
End
_FNroman Param (1) ' ( n --)
Local (1) ' Define b@
' Try all numbers in array
For b@ = 12 To 0 Step -1
Do While a@ > @(b@) - 1 ' Several occurences of same number?
GoSub ((b@ + 1) * 10) ' Print roman digit
a@ = a@ - @(b@) ' Decrement number
Loop
Next
Print ' Terminate line
Return
' Print roman digits 10 Print "I"; : Return 20 Print "IV"; : Return 30 Print "V"; : Return 40 Print "IX"; : Return 50 Print "X"; : Return 60 Print "XL"; : Return 70 Print "L"; : Return 80 Print "XC"; : Return 90 Print "C"; : Return
100 Print "CD"; : Return 110 Print "D"; : Return 120 Print "CM"; : Return 130 Print "M"; : Return</lang>
UNIX Shell
<lang bash>roman() {
local values=( 1000 900 500 400 100 90 50 40 10 9 5 4 1 )
local roman=(
[1000]=M [900]=CM [500]=D [400]=CD
[100]=C [90]=XC [50]=L [40]=XL
[10]=X [9]=IX [5]=V [4]=IV
[1]=I
)
local nvmber=""
local num=$1
for value in ${values[@]}; do
while (( num >= value )); do
nvmber+=${roman[value]}
((num -= value))
done
done
echo $nvmber
}
for test in 1999 24 944 1666 2008; do
printf "%d = %s\n" $test $(roman $test)
done</lang>
- Output:
1999 = MCMXCIX 24 = XXIV 944 = CMXLIV 1666 = MDCLXVI 2008 = MMVIII
Ursala
The algorithm is to implement the subtractive principle by string substitution only after constucting the numeral from successive remainders. The order among the substitutions matters. For example, occurrences of DCCCC must be replaced by CM before any occurrences of CCCC are replaced by CD. The substitution operator (%=) is helpful here. <lang Ursala>#import nat
roman =
-+
'IIII'%='IV'+ 'VIIII'%='IX'+ 'XXXX'%='XL'+ 'LXXXX'%='XC'+ 'CCCC'%='CD'+ 'DCCCC'%='CM', ~&plrDlSPSL/'MDCLXVI'+ iota*+ +^|(^|C/~&,\/division)@rlX=>~&iNC <1000,500,100,50,10,5>+-</lang>
This test program applies the function to each member of a list of numbers. <lang Ursala>#show+
test = roman* <1990,2008,1,2,64,124,1666,10001></lang>
- Output:
MCMXC MMVIII I II LXIV CXXIV MDCLXVI MMMMMMMMMMI
Vala
<lang vala>string to_roman(int n)
requires (n > 0 && n < 5000)
{
const int[] weights = {1000, 900, 500, 400, 100, 90,
50, 40, 10, 9, 5, 4, 1};
const string[] symbols = {"M","CM","D","CD","C","XC","L",
"XL","X","IX","V","IV","I"};
var roman = "", count = 0;
foreach (var w in weights) {
while (n >= w) {
roman += symbols[count];
n -= w;
}
if (n == 0)
break;
count++;
}
return roman;
}
void main() {
print("%s\n", to_roman(455));
print("%s\n", to_roman(3456));
print("%s\n", to_roman(2488));
}</lang>
- Output:
CDLV MMMCDLVI MMCDLXXXVIII
VBA
<lang vb>Private Function roman(n As Integer) As String
roman = WorksheetFunction.roman(n)
End Function Public Sub main()
s = [{10, 2016, 800, 2769, 1666, 476, 1453}]
For Each x In s
Debug.Print roman(CInt(x)); " ";
Next x
End Sub</lang>
- Output:
X MMXVI DCCC MMDCCLXIX MDCLXVI CDLXXVI MCDLIII
Vedit macro language
<lang vedit>// Main program for testing the function // do {
#1 = Get_Num("Number to convert: ", STATLINE)
Call("NUM_TO_ROMAN")
Num_Type(#1, NOCR) Message(" = ") Reg_Type(1) Type_Newline
} while (Reg_Size(1)) Return
// Convert numeric value into Roman number // #1 = number to convert; on return: T-reg(1) = Roman number //
- NUM_TO_ROMAN:
Reg_Empty(1) // @1 = Results (Roman number)
if (#1 < 1) { Return } // non-positive numbers return empty string
Buf_Switch(Buf_Free)
Ins_Text("M1000,CM900,D500,CD400,C100,XC90,L50,XL40,X10,IX9,V5,IV4,I1")
BOF
#2 = #1
Repeat(ALL) {
Search("|A|[|A]", ADVANCE+ERRBREAK) // get next item from conversion list
Reg_Copy_Block(20, CP-Chars_Matched, CP) // @20 = Letter(s) to be inserted
#11 = Num_Eval() // #11 = magnitude (1000...1)
while (#2 >= #11) {
Reg_Set(1, @20, APPEND)
#2 -= #11
}
}
Buf_Quit(OK)
Return</lang>
- Output:
4 = IV 12 = XII 1666 = MDCLXVI 1990 = MCMXC 2011 = MMXI
Visual Basic
<lang vb>Function toRoman(value) As String
Dim arabic As Variant Dim roman As Variant
arabic = Array(1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1)
roman = Array("M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I")
Dim i As Integer, result As String
For i = 0 To 12
Do While value >= arabic(i)
result = result + roman(i)
value = value - arabic(i)
Loop
Next i
toRoman = result
End Function
Sub Main()
MsgBox toRoman(Val(InputBox("Number, please")))
End Sub</lang>
Wren
<lang ecmascript>var romans = [
[1000, "M"], [900, "CM"], [500, "D"], [400, "CD"], [100, "C"], [90, "XC"], [50, "L"], [40, "XL"], [10, "X"], [9, "IX"], [5, "V"], [4, "IV"], [1, "I"]
]
var encode = Fn.new { |n|
if (n > 5000 || n < 1) return null
var res = ""
for (r in romans) {
while (n >= r[0]) {
n = n - r[0]
res = res + r[1]
}
}
return res
}
System.print(encode.call(1990)) System.print(encode.call(1666)) System.print(encode.call(2008)) System.print(encode.call(2020))</lang>
- Output:
MCMXC MDCLXVI MMVIII MMXX
XBasic
<lang xbasic> PROGRAM "romanenc" VERSION "0.0000"
DECLARE FUNCTION Entry() INTERNAL FUNCTION ToRoman$(aValue%%)
' 3888 or MMMDCCCLXXXVIII (15 chars) is the longest string properly encoded with these symbols.
FUNCTION Entry()
PRINT ToRoman$(1990) ' MCMXC PRINT ToRoman$(2018) ' MMXVIII PRINT ToRoman$(3888) ' MMMDCCCLXXXVIII
END FUNCTION
FUNCTION ToRoman$(aValue%%)
DIM weights%%[12] DIM symbols$[12]
weights%%[0] = 1000 weights%%[1] = 900 weights%%[2] = 500 weights%%[3] = 400 weights%%[4] = 100 weights%%[5] = 90 weights%%[6] = 50 weights%%[7] = 40 weights%%[8] = 10 weights%%[9] = 9 weights%%[10] = 5 weights%%[11] = 4 weights%%[12] = 1
symbols$[0] = "M" symbols$[1] = "CM" symbols$[2] = "D" symbols$[3] = "CD" symbols$[4] = "C" symbols$[5] = "XC" symbols$[6] = "L" symbols$[7] = "XL" symbols$[8] = "X" symbols$[9] = "IX" symbols$[10] = "V" symbols$[11] = "IV" symbols$[12] = "I"
destination$ = ""
i@@ = 0
DO WHILE (i@@ <= 12) AND (aValue%% > 0)
DO WHILE aValue%% >= weights%%[i@@]
destination$ = destination$ + symbols$[i@@]
aValue%% = aValue%% - weights%%[i@@]
LOOP
i@@ = i@@ + 1
LOOP
RETURN destination$
END FUNCTION END PROGRAM </lang>
- Output:
MCMXC MMXVIII MMMDCCCLXXXVIII
XLISP
<lang lisp>(defun roman (n)
(define roman-numerals '((1000 "m") (900 "cm") (500 "d") (400 "cd") (100 "c") (90 "xc") (50 "l") (40 "xl") (10 "x") (9 "ix") (5 "v") (4 "iv") (1 "i")))
(defun romanize (arabic-numeral numerals roman-numeral)
(if (= arabic-numeral 0)
roman-numeral
(if (>= arabic-numeral (caar numerals))
(romanize (- arabic-numeral (caar numerals)) numerals (string-append roman-numeral (cadar numerals)))
(romanize arabic-numeral (cdr numerals) roman-numeral))))
(romanize n roman-numerals ""))
- test the function
(display (mapcar roman '(10 2016 800 2769 1666 476 1453)))</lang>
- Output:
(x mmxvi dccc mmdcclxix mdclxvi cdlxxvi mcdliii)
XPL0
<lang XPL0>proc Rom(N, A, B, C); \Display 1..9 in Roman numerals int N, A, B, C, I; [case N of 9: [ChOut(0, C); ChOut(0, A)]; \XI 8,7,6,5:[ChOut(0, B); for I:= 1 to rem(N/5) do ChOut(0, C)]; \V 4: [ChOut(0, C); ChOut(0, B)] \IV other for I:= 1 to N do ChOut(0, C); \I ];
proc Roman(N); \Display N in Roman numerals int N, Q; [Q:= N/1000; N:= rem(0); \0..3999 Rom(Q, ^?, ^?, ^M); Q:= N/100; N:= rem(0); \0..999 Rom(Q, ^M, ^D, ^C); Q:= N/10; N:= rem(0); \0..99 Rom(Q, ^C, ^L, ^X); Rom(N, ^X, ^V, ^I); \0..9 ];
int Tbl, I; [Tbl:= [1990, 2008, 1666, 0, 1, 3999, 2020, 1234]; for I:= 0 to 7 do
[IntOut(0, Tbl(I)); Text(0, ". "); Roman(Tbl(I)); CrLf(0)];
]</lang>
- Output:
1990. MCMXC 2008. MMVIII 1666. MDCLXVI 0. 1. I 3999. MMMCMXCIX 2020. MMXX 1234. MCCXXXIV
XSLT
<lang xslt> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/data/number">
<xsl:call-template name="for">
<xsl:with-param name="stop">13</xsl:with-param>
<xsl:with-param name="value"><xsl:value-of select="@value"></xsl:value-of></xsl:with-param>
</xsl:call-template>
</xsl:template>
<xsl:template name="for">
<xsl:param name="start">1</xsl:param>
<xsl:param name="stop">1</xsl:param>
<xsl:param name="step">1</xsl:param>
<xsl:param name="value">1</xsl:param>
<xsl:text/>
<xsl:choose>
<xsl:when test="($value > /data/roman
/numeral[@pos=$start]/@value or $value = /data/roman /numeral[@pos=$start]/@value) ">
<xsl:value-of select="/data/roman
/numeral[@pos=$start]/@letter"/>
<xsl:call-template name="for">
<xsl:with-param name="stop">
<xsl:value-of select="$stop"/>
</xsl:with-param>
<xsl:with-param name="start">
<xsl:value-of select="$start"/>
</xsl:with-param>
<xsl:with-param name="value">
<xsl:value-of select="$value - /data/roman/numeral[@pos=$start]/@value"/>
</xsl:with-param>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:if test="$start < $stop">
<xsl:call-template name="for">
<xsl:with-param name="stop">
<xsl:value-of select="$stop"/>
</xsl:with-param>
<xsl:with-param name="start">
<xsl:value-of select="$start + $step"/>
</xsl:with-param>
<xsl:with-param name="value">
<xsl:value-of select="$value"/>
</xsl:with-param>
</xsl:call-template>
</xsl:if>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet> </lang>
Yabasic
<lang Yabasic>roman$ = "M, CM, D, CD, C, XC, L, XL, X, IX, V, IV, I" decml$ = "1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1"
sub toRoman$(value)
local res$, i, roman$(1), decml$(1), long
long = token(roman$, roman$(), ", ") long = token(decml$, decml$(), ", ")
for i=1 to long
while(value >= val(decml$(i)))
res$ = res$ + roman$(i)
value = value - val(decml$(i))
wend
next i
return res$
end sub
print 400, " ", toRoman$(400) print 1990, " ", toRoman$(1990) print 2008, " ", toRoman$(2008) print 2009, " ", toRoman$(2009) print 1666, " ", toRoman$(1666) print 3888, " ", toRoman$(3888) //Output: // 400 = CD // 1990 = MCMXC // 2008 = MMVIII // 2009 = MMIX // 1666 = MDCLXVI // 3888 = MMMDCCCLXXXVIII</lang>
zkl
<lang zkl>var [const] romans = L(
L("M", 1000), L("CM", 900), L("D", 500), L("CD", 400), L("C", 100),
L("XC", 90), L("L", 50), L("XL", 40), L("X", 10), L("IX", 9),
L("V", 5), L("IV", 4), L("I", 1));
fcn toRoman(i){ // convert int to a roman number
reg text = "";
foreach R,N in (romans){ text += R*(i/N); i = i%N; }
return(text);
}</lang>
toRoman(1990) //-->"MCMXC" toRoman(2008) //-->"MMVIII" toRoman(1666) //-->"MDCLXVI"
Zoea
<lang Zoea> program: decimal_roman
input: 12 output: 'XII'
</lang>
Zoea Visual
Zsh
Based on the python solution. <lang zsh>function printroman () {
local -a conv
local number=$1 div rom num out
conv=(I 1 IV 4 V 5 IX 9 X 10 XL 40 L 50 XC 90 C 100 CD 400 D 500 CM 900 M 1000)
for num rom in ${(Oa)conv}; do
(( div = number / num, number = number % num ))
while (( div-- > 0 )); do
out+=$rom
done
done
echo $out
}</lang>