Roman numerals/Encode
You are encouraged to solve this task according to the task description, using any language you may know.
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. 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.
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
AutoHotkey
Translated from C++ example <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>
AWK
To cram this into an AWK one-liner is a bit of a stretch, but here goes: <lang awk>$ awk 'func u(v,n){while(i>=v){r=r n;i-=v}}{i=$1;r="";u(1000,"M");u(900,"CM");u(500,"D");u(400,"CD");u(100,"C");u(90,"XC");u(50,"L");u(40,"XL");u(10,"X");u(9,"IX");u(5,"V");u(4,"IV");u(1,"I");print r}' 2009 MMIX 1999 MCMXCIX</lang>
BASIC
<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
C
<lang c>#include <stdlib.h>
- include <stdio.h>
void roman(char *s, unsigned n) /* Writes the Roman numeral representing n into the buffer s. Handles up to n = 3999. Since C doesn't have exceptions, n = 0 causes the whole program to exit unsuccessfully. s should be have room for at least 16 characters, including the trailing null. */
{if (n == 0) {puts("Roman numeral for zero requested."); exit(EXIT_FAILURE);}
#define digit(loop, num, c) \ loop (n >= num) \ {*(s++) = c; \ n -= num;} #define digits(loop, num, c1, c2) \ loop (n >= num) \ {*(s++) = c1; \ *(s++) = c2; \ n -= num;}
digit ( while, 1000, 'M' ) digits ( if, 900, 'C', 'M' ) digit ( if, 500, 'D' ) digits ( if, 400, 'C', 'D' ) digit ( while, 100, 'C' ) digits ( if, 90, 'X', 'C' ) digit ( if, 50, 'L' ) digits ( if, 40, 'X', 'L' ) digit ( while, 10, 'X' ) digits ( if, 9, 'I', 'X' ) digit ( if, 5, 'V' ) digits ( if, 4, 'I', 'V' ) digit ( while, 1, 'I' )
#undef digit #undef digits *s = 0;}
int main(void)
{char buffer[16]; for (int i = 1 ; i < 4000 ; ++i) {roman(buffer, i); printf("%4d: %s\n", i, buffer);} return 1;}</lang>
An alternative version which builds the string backwards.<lang c>char *ToRoman(int num, char *buf, int buflen) {
static const char *romanDgts = "ivxlcdmVXLCDM_"; char *roman = buf + buflen; int rdix, r, v; *--roman = '\0'; /* null terminate return string */ if (num >= 4000000) { printf("Number Too Big.\n"); return NULL; } for (rdix = 0; rdix < strlen(romanDgts); rdix += 2) { if (num == 0) break; v = (num % 10) / 5; r = num % 5; num = num / 10; if (r == 4) { if (roman < buf+2) { printf("Buffer too small."); return NULL; } *--roman = romanDgts[rdix+1+v]; *--roman = romanDgts[rdix]; } else { if (roman < buf+r+v) { printf("Buffer too small."); return NULL; } while(r-- > 0) { *--roman = romanDgts[rdix]; } if (v==1) { *--roman = romanDgts[rdix+1]; } } } return roman;
}</lang>
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>
Output:
1 = I 2 = II 4 = IV 8 = VIII 16 = XVI 32 = XXXII 64 = LXIV 128 = CXXVIII 256 = CCLVI 512 = DXII 1024 = MXXIV
C++
<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, 0 }; // 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>
Common Lisp
<lang lisp>(defun roman-numeral (n)
(format nil "~@R" n))</lang>
Clojure
<lang Clojure> (def arabic-roman-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" })
(def arabic-roman-map-sorted-keys
(sort (keys arabic-roman-map)))
(defn find-value-in-coll
[coll k] (let [aval (find coll k)] (if (nil? aval) "" (val aval))))
(defn to-roman
[result n] (let [closest-key-for-n (last (filter #(> n %) arabic-roman-map-sorted-keys)) roman-value-for-n (find-value-in-coll arabic-roman-map n) roman-value-for-closet-to-n (find-value-in-coll arabic-roman-map
closest-key-for-n)]
(if (or (<= n 0)(contains? arabic-roman-map n))
(conj result roman-value-for-n) (recur (conj result roman-value-for-closet-to-n) (- n closest-key-for-n)))))
Usage: >(to-roman [] 1999) result: ["M" "CM" "XC" "IX"]
</lang>
D
This implementation in generally follows the rules implied by Modern Roman numerals, with some irregularity depend on whether numerals larger than M(1000) is used, eg. 4000 is converted to MV' if V' is used, MMMM if not. <lang d>module roman ; import std.stdio ;
const string[] Roman = ["V","X","L","C","D","M","I"] ; const int RLen = Roman.length - 1 ; const int[][] RDigit =
[[0],[0,0],[0,0,0],[0,1],[1],[1,0],[1,0,0],[1,0,0,0],[0,2],[0,0,0,0]] ;
const string[] Power = ["", "'","\"","`","~","^","#"] ; // arbitary _power_ symbols, or
// Power = ["1","2","3","4","5","6","7"] ; // for easier further processing
const int[][] Shift = [[0,0,0],[-1,0,0]] ;
string romanPart(int n, int part, bool extented) {
if (n == 0) return "" ; int[3] b ; b[1] = (2 * part) % RLen ; b[0] = part == 0 ? RLen : (RLen + b[1] - 1) % RLen ; b[2] = b[1] + 1 ; int power = part / 3 ; int[] shift = Shift[ b[1] == 0 && part != 0 ? 1 : 0] ; int[] Digit = !extented && n == 4 && part == 3 ? RDigit[$-1] : RDigit[n-1] ; string res ; foreach(inx ; Digit) res ~= Roman[b[inx]] ~ Power[power + shift[inx]] ; return res ;
} string toRoman(long n, bool extented = true) {
if(n < 0) throw new Exception("No negative Roman Numeral") ; if(n == 0) return "" ; if(!extented && n >= 5000) throw new Exception("Only smaller than 5000 allowed") ; string romans ; int part = 0 ; while (n > 0) { long m = n / 10 ; romans = romanPart(n - m*10, part, extented) ~ romans ; n = m ; part++ ; } return romans ;
} void main() {
auto test = [1L,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,long.max] ; foreach(x ; test) writefln("%20s - %s", x, toRoman(x)) ;
}</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, $X).
digit(1, X, _, _) -> [X]; digit(2, X, _, _) -> [X, X]; digit(3, X, _, _) -> [X, X, X]; digit(4, X, Y, _) -> [X, Y]; digit(5, _, Y, _) -> [Y]; digit(6, X, Y, _) -> [Y, X]; digit(7, X, Y, _) -> [Y, X, X]; digit(8, X, Y, _) -> [Y, X, X, X]; digit(9, X, _, Z) -> [X, Z].</lang>
sample:
1> c(roman). {ok,roman} 2> roman:to_roman(1999). "MCMXCIX" 3> roman:to_roman(25). "XXV" 4> roman:to_roman(944). "CMXLIV"
Factor
A roman numeral library ships with Factor. <lang factor>USE: roman ( scratchpad ) 3333 >roman . "mmmcccxxxiii"</lang>
Parts of the implementation:
<lang factor>CONSTANT: roman-digits
{ "m" "cm" "d" "cd" "c" "xc" "l" "xl" "x" "ix" "v" "iv" "i" }
CONSTANT: roman-values
{ 1000 900 500 400 100 90 50 40 10 9 5 4 1 }
ERROR: roman-range-error n ;
- roman-range-check ( n -- n )
dup 1 10000 between? [ roman-range-error ] unless ;
- >roman ( n -- str )
roman-range-check roman-values roman-digits [ [ /mod swap ] dip <repetition> concat ] 2map "" concat-as nip ;</lang>
FALSE
<lang false>^$." " [$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@ emit ;
- .V dup 1 + c@ emit ;
- .X dup 2 + c@ emit ;
\ 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 -- )
dup 0 4000 within 0= if ." EX LIMITO!" exit then s" IVXLCDM" drop swap roman-rec ;</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
Haskell
With an explicit decimal digit representation list:
<lang haskell>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</lang>
Output:
<lang haskell>*Main> map toRoman [1999,25,944] ["MCMXCIX","XXV","CMXLIV"]</lang>
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
Icon
<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>
fib provides numbers:roman as seen below and based on 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>
Sample 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 ***
Unicon
This Icon solution works in Unicon.
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>
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 helper function copies is added since Java does not support String multiplication. The conversion function returns null for non-positive numbers, since Java does not have unsigned primitives. <lang java>public class RN{ public static void main(String args[]){ System.out.println(roman(1999)); System.out.println(roman(25)); System.out.println(roman(954)); } public static String roman(long n){ if(n < 1) return null; String result = ""; if(n >= 1000){ result+= (copies("M",(n / 1000))); n%= 1000; } if(n >= 900){ result+= "CM"; n%= 900; } if(n >= 500){ result+= "D"; n%= 500; } if(n >= 400){ result+= "CD"; n%= 400; } if(n >= 100){ result+= (copies("C",(n / 100))); n%= 100; } if(n >= 90){ result+= "XC"; n%= 90; } if(n >= 50){ result+= "L"; n%= 50; } if(n >= 40){ result+= "XL"; n%= 40; } if(n >= 10){ result+= (copies("X",(n / 10))); n%= 10; } if(n == 9){ result+= "IX"; n= 0; } if(n >= 5){ result+= "V"; n%= 5; } if(n == 4){ result+= "IV"; n= 0; } result+= (copies("I",n)); return result; }
public static String copies(String a, int n){ String result = ""; for(int i= 0;i < n;i++,result+= a); return result; } }</lang> Output:
MCMXCIX XXV CMXLIV
JavaScript
<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>
LaTeX
The macro \Roman
is defined for uppercase roman numeral, accepting as argument a name of an existing counter.
<lang latex>\documentclass{article} \begin{document} \newcounter{currentyear}\setcounter{currentyear}{\year} Anno Domini \Roman{currentyear} \end{document}</lang>
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>
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
Mathematica
Define a custom function that works on positive numbers (RomanForm[0] will not be evaluated): <lang Mathematica>RomanForm[i_Integer?Positive] :=
Module[{num = i, string = "", value, letters, digits}, digits = {{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[num > 0, {value, letters} = Which @@ Flatten[{num >= #1, ##} & /@ digits, 1]; num -= value; string = string <> letters;]; string]</lang>
Examples: <lang Mathematica>RomanForm[4] RomanForm[99] RomanForm[1337] RomanForm[1666] RomanForm[6889]</lang> gives back: <lang Mathematica>IV XCIX MCCCXXXVII MDCLXVI MMMMMMDCCCLXXXIX</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']
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>
Perl
Perligata outputs numbers in Arabic, but the verb come ("beautify") may be used to convert numbers to proper Roman numerals:
<lang perl>per quisque in I tum C conscribementum sic
hoc tum duos multiplicamentum comementum egresso scribe.
cis</lang>
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;
sub roman (Int $n where { $n > 0 }) {
return %symbols{$n} if %symbols{$n}; for @subtractors -> $cut, $minus { $cut < $n and return %symbols{$cut} ~ roman($n - $cut); $cut - $minus <= $n and return %symbols{$minus} ~ roman($n + $minus); }
}</lang>
Sample usage
<lang perl6>for 1 .. 2_010 -> $x {
say roman($x);
}</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 . $leastSig; } </lang>
PicoLisp
<lang PicoLisp>(de roman (N)
(pack (make (mapc '((C D) (while (>= N D) (dec 'N D) (link C) ) ) '(M CM D CD C XC L XL X IX V IV I) (1000 900 500 400 100 90 50 40 10 9 5 4 1) ) ) ) )</lang>
Output:
: (roman 1009) -> "MIX" : (roman 1666) -> "MDCLXVI"
Pike
<lang pike>import String; int main(){
write(int2roman(2009) + "\n"); write(int2roman(1666) + "\n"); write(int2roman(1337) + "\n");
}</lang>
Plain TeX
TeX has its own way to convert a number into roman numeral, but it produces lowercase letters; the following macro (and usage example), produce uppercase roman numeral.
<lang tex>\def\upperroman#1{\uppercase\expandafter{\romannumeral#1}} Anno Domini \upperroman{\year} \bye</lang>
PL/I
<lang PL/I> /* From Wiki Fortran */ roman: procedure (n) returns(character (32) varying);
declare n fixed binary nonassignable; declare (d, m) fixed binary; declare (r, m_div) character (32) varying; declare d_dec(13) fixed binary static initial (1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1); declare d_rom(13) character (2) varying static initial ('M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I'); r = ; m = n; do d = 1 to 13; m_div = m / d_dec (d); r = r || copy (d_rom (d), m_div); m = m - d_dec (d) * m_div; end; return (r);
end roman; </lang>
PureBasic
<lang PureBasic>#SymbolCount = 12 ;0 based count DataSection
denominations: Data.s "M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I" ;0-12 denomValues: Data.i 1000,900,500,400,100,90,50,40,10,9,5,4,1 ;values in decending sequential order
EndDataSection
- -setup
Structure romanNumeral
symbol.s value.i
EndStructure
Global Dim refRomanNum.romanNumeral(#SymbolCount)
Restore denominations For i = 0 To #SymbolCount
Read.s refRomanNum(i)\symbol
Next
Restore denomValues For i = 0 To #SymbolCount
Read refRomanNum(i)\value
Next
Procedure.s decRoman(n)
;converts a decimal number to a roman numeral Protected roman$, 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
<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>
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>
REXX
<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>
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</lang>
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>
Sample:
scala> List(1990, 2008, 1666) map toRoman res55: List[String] = List(MCMXC, MMVIII, MDCLXVI)
Scheme
This uses format directives supported in Chez Scheme since v6.9b; YMMV.
<lang scheme>(define (to-roman n)
(format "~@r" n))</lang>
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>
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> Outputs:
1999 = MCMXCIX 24 = XXIV 944 = CMXLIV
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
Vedit macro language
<lang vedit>do {
#1 = Get_Num("Number to convert: ") Call("ROMAN_NUMBER") Reg_Type(1) Message("\n")
} while (Reg_Size(1)) Return
// Convert numeric value into Roman number // #1 = number to convert; on return: T-reg(1) = Roman number //
- ROMAN_NUMBER:
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 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 (#1 >= #11) { Reg_Set(1, @20, APPEND) #1 -= #11 } } Buf_Quit(OK)
Return</lang>
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>
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