Roman numerals/Encode
From Rosetta Code
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.
[edit] 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));
Output:
1990 in roman is MCMXC 2008 in roman is MMVIII 1666 in roman is MDCLXVI
And the reverse:
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"));
Output:
MCMXC in arabic is 1990 MMVIII in arabic is 2008 MDCLXVI in arabic is 1666
[edit] 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;
Output:
MCMXCIX XXV CMXLIV
[edit] ALGOL 68
[]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
)
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
[edit] ALGOL W
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.
Output:
I 1 MMMCMXCIX 9 MMMDCCCLXXXVIII 15 MMIX 4 CDV 3
[edit] 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"
}
[edit] 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])
}
output:
1990 = MCMXC 2008 = MMVIII 1666 = MDCLXVI
[edit] BASIC
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)
Output
2009 = MMIX 1666 = MDCLXVI 3888 = MMMDCCCLXXXVIII
[edit] ZX Spectrum Basic
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$
[edit] 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")
)
)
);
Output:
1990 MCMXC 2008 MMVIII 1666 MDCLXVI 3888 MMMDCCCLXXXVIII 3999 MMMCMXCIX Can't convert 4000 to Roman numeral
[edit] C
#include <stdlib.h>
#include <stdio.h>
/*
* 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.
*/
void roman(char *s, unsigned int n)
{
if (n == 0)
{
fputs(stderr, "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];
unsigned int i;
for (i = 1 ; i < 4000 ; ++i)
{
roman(buffer, i);
printf("%4u: %s\n", i, buffer);
}
return EXIT_SUCCESS;
}
An alternative version which builds the string backwards.
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;
}
Most straightforward (nothing elegant about it, but it's simple, and can calcuate output length)
#include <stdio.h>Output:
int to_roman(char *out, int n)
{
int len = 0;
if (n <= 0) return 0; /* error indication */
# define RPUT(c) if (out) out[len] = c; len++
while(n>= 1000) { n -= 1000;RPUT('M'); };
if (n >= 900) { n -= 900; RPUT('C'); RPUT('M'); };
if (n >= 500) { n -= 500; RPUT('D'); };
if (n >= 400) { n -= 400; RPUT('C'); RPUT('D'); };
while (n >= 100){ n -= 100; RPUT('C'); };
if (n >= 90) { n -= 90; RPUT('X'); RPUT('C'); };
if (n >= 50) { n -= 50; RPUT('L'); };
if (n >= 40) { n -= 40; RPUT('X'); RPUT('L'); };
while (n >= 10) { n -= 10; RPUT('X'); };
if (n >= 9) { n -= 9; RPUT('I'); RPUT('X'); };
if (n >= 5) { n -= 5; RPUT('V'); };
if (n >= 4) { n -= 4; RPUT('I'); RPUT('V'); };
while (n) { n--; RPUT('I'); };
RPUT('\0');
# undef RPUT
return len;
}
int main()
{
char buf[16];
int d = to_roman(buf, 1666);
printf("roman for 1666 is %d bytes: %s\n", d, buf);
d = 68999123;
printf("%d would have required %d bytes\n", d, to_roman(0, d));
return 0;
}
roman for 1666 is 8 bytes: MDCLXVI68999123 would have required 69006 bytes
[edit] C#
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));
}
}
}
Output:
1 = I 2 = II 4 = IV 8 = VIII 16 = XVI 32 = XXXII 64 = LXIV 128 = CXXVIII 256 = CCLVI 512 = DXII 1024 = MXXIV
[edit] C++
#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;
}
}
[edit] 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"
[edit] Common Lisp
(defun roman-numeral (n)
(format nil "~@R" n))
[edit] 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"]
[edit] 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() {}
[edit] Delphi
program RomanNumeralsEncode;
{$APPTYPE CONSOLE}
function IntegerToRoman(aValue: Integer): string;
var
i: Integer;
const
WEIGHTS: array[0..12] of Integer = (1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1);
SYMBOLS: array[0..12] of string = ('M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV', 'I');
begin
for i := Low(WEIGHTS) to High(WEIGHTS) do
begin
while aValue >= WEIGHTS[i] do
begin
Result := Result + SYMBOLS[i];
aValue := aValue - WEIGHTS[i];
end;
if aValue = 0 then
Break;
end;
end;
begin
Writeln(IntegerToRoman(1990)); // MCMXC
Writeln(IntegerToRoman(2008)); // MMVIII
Writeln(IntegerToRoman(1666)); // MDCLXVI
end.
[edit] DWScript
const weights = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];
const symbols = ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"];
function toRoman(n : Integer) : String;
var
i, w : Integer;
begin
for i := 0 to weights.High do begin
w := weights[i];
while n >= w do begin
Result += symbols[i];
n -= w;
end;
if n = 0 then Break;
end;
end;
PrintLn(toRoman(455));
PrintLn(toRoman(3456));
PrintLn(toRoman(2488));
[edit] Erlang
-module(roman).
-export([to_roman/1]).
to_roman(0) -> [];
to_roman(X) when X >= 1000 -> [$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, $X).
digit(1, X, _, _) -> [X];
digit(2, X, _, _) -> [X, X];
digit(3, X, _, _) -> [X, X, X];
digit(4, X, Y, _) -> [X, Y];
digit(5, _, Y, _) -> [Y];
digit(6, X, Y, _) -> [Y, X];
digit(7, X, Y, _) -> [Y, X, X];
digit(8, X, Y, _) -> [Y, X, X, X];
digit(9, X, _, Z) -> [X, Z].
sample:
1> c(roman).
{ok,roman}
2> roman:to_roman(1999).
"MCMXCIX"
3> roman:to_roman(25).
"XXV"
4> roman:to_roman(944).
"CMXLIV"
[edit] Euphoria
constant arabic = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 }
constant roman = {"M", "CM", "D","CD", "C","XC","L","XL","X","IX","V","IV","I"}
function toRoman(integer val)
sequence result
result = ""
for i = 1 to 13 do
while val >= arabic[i] do
result &= roman[i]
val -= arabic[i]
end while
end for
return result
end function
printf(1,"%d = %s\n",{2009,toRoman(2009)})
printf(1,"%d = %s\n",{1666,toRoman(1666)})
printf(1,"%d = %s\n",{3888,toRoman(3888)})
Output:
2009 = MMIX 1666 = MDCLXVI 3888 = MMMDCCCLXXXVIII
[edit] Factor
A roman numeral library ships with Factor.
USE: roman
( scratchpad ) 3333 >roman .
"mmmcccxxxiii"
Parts of the implementation:
CONSTANT: roman-digits
{ "m" "cm" "d" "cd" "c" "xc" "l" "xl" "x" "ix" "v" "iv" "i" }
CONSTANT: roman-values
{ 1000 900 500 400 100 90 50 40 10 9 5 4 1 }
ERROR: roman-range-error n ;
: roman-range-check ( n -- n )
dup 1 10000 between? [ roman-range-error ] unless ;
: >roman ( n -- str )
roman-range-check
roman-values roman-digits [
[ /mod swap ] dip <repetition> concat
] 2map "" concat-as nip ;
[edit] FALSE
^$." "
[$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"]#%
[edit] 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)}") }
}
}
[edit] 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
[edit] 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
Output:
MMIX MDCLXVI MMMDCCCLXXXVIII
[edit] 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...)
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")
}
}
}
Output:
1990 == MCMXC 2008 == MMVIII 1666 == MDCLXVI
[edit] 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'
[edit] Haskell
With an explicit decimal digit representation list:
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
Output:
*Main> map toRoman [1999,25,944]
["MCMXCIX","XXV","CMXLIV"]
[edit] 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
[edit] Icon and Unicon
link numbers # commas, roman
procedure main(arglist)
every x := !arglist do
write(commas(x), " -> ",roman(x)|"*** can't convert to Roman numerals ***")
end
numbers.icn provides roman as seen below and is based upon a James Gimple SNOBOL4 function.
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
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 ***
[edit] 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
[edit] J
rfd obtains Roman numerals from decimals.
R1000=. ;L:1 ,{ <@(<;._1);._2]0 :0For example:
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' $~ <.@%&1000) , R1000 {::~ 1000&|
rfd 1234
MCCXXXIV
rfd 567
DLXVII
rfd 89
LXXXIX
Derived from the J Wiki. Further examples of use will be found there.
[edit] Java
The conversion function throws an IllegalArgumentException for non-positive numbers, since Java does not have unsigned primitives.
public class RN {
enum Numeral {
I(1), IV(4), V(5), IX(9), X(10), XL(40), L(50), XC(90), C(100), CD(400), D(500), CM(900), M(1000);
int weight;
Numeral(int weight) {
this.weigth = weight;
}
};
public static String roman(long n) {
if( n <= 0) {
throw new IllegalArgumentException();
}
StringBuilder buf = new StringBuilder();
final Numeral[] values = Numeral.values();
for (int i = values.length - 1; i >= 0; i--) {
while (n >= values[i].weight) {
buf.append(values[i]);
n -= values[i].weight;
}
}
return buf.toString();
}
public static void test(long n) {
System.out.println(n + " = " + roman(n));
}
public static void main(String[] args) {
test(1999);
test(25);
test(944);
test(0);
}
}
Output:
1999 = MCMXCIX 25 = XXV 944 = CMXLIV Exception in thread "main" java.lang.IllegalArgumentException at RN.roman(RN.java:15) at RN.test(RN.java:31) at RN.main(RN.java:38)
[edit] JavaScript
var roman = {
map: [
1000, 'M', 900, 'CM', 500, 'D', 400, 'CD', 100, 'C', 90, 'XC',
50, 'L', 40, 'XL', 10, 'X', 9, 'IX', 5, 'V', 4, 'IV', 1, 'I',
],
int_to_roman: function(n) {
var value = '';
for (var idx = 0; n > 0 && idx < this.map.length; idx += 2) {
while (n >= this.map[idx]) {
value += this.map[idx + 1];
n -= this.map[idx];
}
}
return value;
}
}
roman.int_to_roman(1999); // "MCMXCIX"
[edit] LaTeX
The macro \Roman is defined for uppercase roman numeral, accepting as argument a name of an existing counter.
\documentclass{article}
\begin{document}
\newcounter{currentyear}\setcounter{currentyear}{\year}
Anno Domini \Roman{currentyear}
\end{document}
[edit] Liberty BASIC
dim arabic( 12)
for i =0 to 12
read k
arabic( i) =k
next i
data 1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1
dim roman$( 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
2009 MMIX 1666 MDCLXVI 3888 MMMDCCCLXXXVIII
[edit] 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
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
[edit] LotusScript
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
[edit] 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()
[edit] 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($1-1))'
)')')')')')')')')')')')')dnl
dnl
roman(3675)
Output:
MMMDCLXXV
[edit] Mathematica
Define a custom function that works on positive numbers (RomanForm[0] will not be evaluated):
RomanForm[i_Integer?Positive] :=
Module[{num = i, string = "", value, letters, digits},
digits = {{1000, "M"}, {900, "CM"}, {500, "D"}, {400, "CD"}, {100,
"C"}, {90, "XC"}, {50, "L"}, {40, "XL"}, {10, "X"}, {9,
"IX"}, {5, "V"}, {4, "IV"}, {1, "I"}};
While[num > 0, {value, letters} =
Which @@ Flatten[{num >= #[[1]], ##} & /@ digits, 1];
num -= value;
string = string <> letters;];
string]
Examples:
RomanForm[4]
RomanForm[99]
RomanForm[1337]
RomanForm[1666]
RomanForm[6889]
gives back:
IV
XCIX
MCCCXXXVII
MDCLXVI
MMMMMMDCCCLXXXIX
[edit] MUMPS
TOROMAN(INPUT)Output:
;Converts INPUT into a Roman numeral. INPUT must be an integer between 1 and 3999
;OUTPUT is the string to return
;I is a loop variable
;CURRVAL is the current value in the loop
QUIT:($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
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
[edit] 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();
}
}
}
[edit] OCaml
With an explicit decimal digit representation list:
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
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']
[edit] OpenEdge/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.
Output:
--------------------------- Message (Press HELP to view stack trace) --------------------------- 1990 MCMXC 2008 MMVIII 2000 MM 1666 MDCLXVI --------------------------- OK Help ---------------------------
[edit] 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}
[edit] PARI/GP
Old-style Roman numerals
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()
};
This simple version of medieval Roman numerals does not handle large numbers.
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()
};
[edit] Pascal
See Delphi
[edit] Perl
Perligata outputs numbers in Arabic, but the verb come ("beautify") may be used to convert numbers to proper Roman numerals:
per quisque in I tum C conscribementum sic
hoc tum duos multiplicamentum comementum egresso scribe.
cis
[edit] Perl 6
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);
}
}
[edit] Sample usage
for 1 .. 2_010 -> $x {
say roman($x);
}
[edit] 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;
}
[edit] 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) ) ) ) )
Output:
: (roman 1009) -> "MIX" : (roman 1666) -> "MDCLXVI"
[edit] Pike
import String;
int main(){
write(int2roman(2009) + "\n");
write(int2roman(1666) + "\n");
write(int2roman(1337) + "\n");
}
[edit] plainTeX
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.
\def\upperroman#1{\uppercase\expandafter{\romannumeral#1}}
Anno Domini \upperroman{\year}
\bye
[edit] 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;
[edit] 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
[edit] Prolog
Works with SWI-Prolog and library clpfd.
Library clpfd assures that the program works in both managements : Roman towards Arabic and Arabic towards Roman.
:- 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]).
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 .
[edit] Protium
Roman numbers are built in to Protium as a particular form of national number. However, for the sake of the task the _RO opcode has been defined.
<@ 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</@>
</@>
Same code in padded-out, variable-length English dialect
<# 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</#>
</#>
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
[edit] 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
[edit] Python
roman = "MDCLXVmdclxvi"; # UPPERCASE for thousands #An alternative which uses the divmod() function
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))
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]
It is more Pythonic to use zip to iterate over two lists together:
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))
[edit] 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.
as.roman(1666) # MDCLXVI
[edit] 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.
: 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 ;
[edit] REXX
[edit] version 1
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
[edit] version 2
This version of a REXX program allows almost any non-negative (whole) decimal number.
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 serveral (see the REXX code), as does modern English. In American English, many words can be used:
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 code was ripped out of a general routine that also supported versions for Attic, ancient Roman, and modern Roman.)
The code is bulkier than most at it deals with any non-negative decimal number, and more boilerplate code is(was) present to handle the above versions.
/*REXX program converts (Arabic) decimal numbers (≥0) ──> Roman numerals*/
numeric digits 10000 /*could be higher if wanted*/
parse arg nums
if nums='' then do /*not specified? Gen some.*/
do j=0 by 11 to 111
nums=nums j
end
nums=nums 49
do k=88 by 100 to 1200
nums=nums k
end
nums=nums 1000 2000 3000 4000 5000 6000
do m=88 by 200 to 1200
nums=nums m
end
nums=nums 1304 1405 1506 1607 1708 1809 1910 2011
do p=4 to 50 /*there is no limit to this*/
nums=nums 10**p
end
end /*end generation of numbers*/
do j=1 for words(nums); x=word(nums,j)
say right(x,55) dec2rom(x)
end
exit
/*───────────────────────────DEC2ROM subroutine─────────────────────────*/
dec2rom: procedure; parse arg n,#
if pos(",",n)\==0 then n=space(translate(n,,','),0) /*remove commas.*/
nulla='ZEPHIRUM NULLAE NULLA NIHIL' /*Roman words for nothing or none.*/
if n==0 then return word(nulla,1)
maxnp=(length(n)-1)%3 /*find max(+1) # of parens to use.*/
highPos=(maxnp+1)*3 /*highest position of number. */
nn=reverse(right(n,highPos,0)) /*digits for Arabic───>Roman conv.*/
nine=9
four=4
do j=highPos to 1 by -3
_=substr(nn,j,1)
select
when _==nine then hx='CM'
when _>= 5 then hx='D'copies('C',_-5)
when _==four then hx='CD'
otherwise hx=copies('C',_)
end
_=substr(nn,j-1,1)
select
when _==nine then tx='XC'
when _>= 5 then tx='L'copies('X',_-5)
when _==four then tx='XL'
otherwise tx=copies('X',_)
end
_=substr(nn,j-2,1)
select
when _==nine then ux='IX'
when _>= 5 then ux='V'copies('I',_-5)
when _==four then ux='IV'
otherwise ux=copies('I',_)
end
xx=hx||tx||ux
if xx\=='' then #=#||copies('(',(j-1)%3)xx||copies(')',(j-1)%3)
end /*j*/
if pos('(I',#)\==0 then do j=1 for 4 /*special case: M,MM,MMM,MMMM.*/
if j==4 then _='(IV)'
else _='('copies("I",j)')'
if pos(_,#)\==0 then #=changestr(_,#,copies('M',j))
end
return #
Output when using the default input (within the REXX program):
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))))))))))))))))
[edit] Ruby
Roman numeral generation was used as an example for demonstrating Test Driven Development in Ruby. The solution came to be:
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
[edit] Run BASIC
[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
[edit] 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 => ""
}
Sample:
scala> List(1990, 2008, 1666) map toRoman res55: List[String] = List(MCMXC, MMVIII, MDCLXVI)
[edit] Scala Using foldLeft
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)
- Output:
1990 => MCMXC 2008 => MMVIII 1666 => MDCLXVI
[edit] Scheme
This uses format directives supported in Chez Scheme since v6.9b; YMMV.
(define (to-roman n)
(format "~@r" n))
[edit] 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.
$ 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;
Original source [1].
[edit] 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
}
[edit] SNOBOL4
Adapted from Catspaw SNOBOL Tutorial, Chapter 6
* 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
Outputs:
1999 = MCMXCIX 24 = XXIV 944 = CMXLIV
Here's a non-recursive version, and a Roman-to-Arabic converter to boot.
* # 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
Output:
2010=MMX 1999=MCMXCIX 1492=MCDXCII 1066=MLXVI 476=CDLXXVI MMX=2010 MCMXCIX=1999 MCDXCII=1492 MLXVI=1066 CDLXXVI=476
[edit] TI-83 BASIC
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
[edit] TUSCRIPT
$$ MODE TUSCRIPT
LOOP arab_number="1990'2008'1666"
roman_number = ENCODE (arab_number,ROMAN)
PRINT "Arabic number ",arab_number, " equals ", roman_number
ENDLOOP
Output:
Arabic number 1990 equals MCMXC Arabic number 2008 equals MMVIII Arabic number 1666 equals MDCLXVI
[edit] 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.
#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>+-
This test program applies the function to each member of a list of numbers.
#show+
test = roman* <1990,2008,1,2,64,124,1666,10001>
output:
MCMXC MMVIII I II LXIV CXXIV MDCLXVI MMMMMMMMMMI
[edit] Vedit macro language
// 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
Output:
4 = IV 12 = XII 1666 = MDCLXVI 1990 = MCMXC 2011 = MMXI
[edit] Visual Basic
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
[edit] 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>
[edit] Zsh
Based on the python solution.
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
}
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