This post contains a total of 15+ Hand-Picked C++ Decimal to Roman Converter Examples with Source Code. All the Decimal to Roman Converters are made using C++ Programming language.
You can use the source codes of the programs given below for your own personal or educational use with credits to the original owner.
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1. By Roman
Made by Roman. CPP Program to Convert Decimal number to Roman Numerals. ( Source )
#include <iostream>
using namespace std;
int main() {
int num;
cin >> num;
int m = num/1000;
int c = (num-m*1000)/100;
int d = (num-m*1000-c*100)/10;
int u = (num-m*1000-c*100-d*10);
string mr;
string cr;
string dr;
string ur;
if (num>0 && num<=3999){
switch (m){
case 0:
mr = "";
break;
case 1:
mr = "M";
break;
case 2:
mr = "MM";
break;
case 3:
mr = "MMM";
break;
}
switch (c){
case 0:
cr = "";
break;
case 1:
cr = "C";
break;
case 2:
cr = "CC";
break;
case 3:
cr = "CCC";
break;
case 4:
cr = "CD";
break;
case 5:
cr = "D";
break;
case 6:
cr = "DC";
break;
case 7:
cr = "DCC";
break;
case 8:
cr = "DCCC";
break;
case 9:
cr = "CM";
break;
}
switch (d){
case 0:
dr = "";
break;
case 1:
dr = "X";
break;
case 2:
dr = "XX";
break;
case 3:
dr = "XXX";
break;
case 4:
dr = "XL";
break;
case 5:
dr = "L";
break;
case 6:
dr = "LX";
break;
case 7:
dr = "LXX";
break;
case 8:
dr = "LXXX";
break;
case 9:
dr = "XC";
break;
}
switch (u){
case 0:
ur = "";
break;
case 1:
ur = "I";
break;
case 2:
ur = "II";
break;
case 3:
ur = "III";
break;
case 4:
ur = "IV";
break;
case 5:
ur = "V";
break;
case 6:
ur = "VI";
break;
case 7:
ur = "VII";
break;
case 8:
ur = "VIII";
break;
case 9:
ur = "IX";
break;
}
cout << num << " equivale a " << mr << cr << dr << ur << " en numeros romanos." << endl;
}
else (cout << "No existe tal numero en numeracion romana" <<endl);
return 0;
}2. By Naman Sharma
Made by Naman Sharma. ( Source )
#include <iostream>
#include <map>
#include <string>
#include <cmath>
using namespace std;
string GetRomanNumber(int number)
{
map<int, string>
decimal2Roman {{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"}};
map<int, string>::reverse_iterator it;
string roman="";
for(it = decimal2Roman.rbegin(); it != decimal2Roman.rend(); it++)
{
while(number >= it->first)
{
number -= it->first;
roman += it->second;
}
}
return roman;
}
int main() {
int n;
cout <<"Enter a decimal number: ";
cin>>n;
cout<<"\nThe Roman Equivalent is: "<<GetRomanNumber(n)<<"\n";
return 0;
}3. By Swabhiman
Made by Swabhiman. ( Source )
// Decimal to Roman Number Conversion
#include <iostream>
using namespace std;
int roman_Number(int ,int ,char);
int main() {
int num=8;
// cout<<"Enter a number :";
//cin>>num;
cout<<"Roman Number of Your Number is :";
if(num>=1000)
num= roman_Number (num,1000,'m');
if(num>=500)
num= roman_Number (num,500,'d');
if(num>=100)
num= roman_Number (num,100,'c');
if(num>=50)
num= roman_Number (num,50,'l');
if(num>=10)
num= roman_Number (num,10,'x');
if(num>=5)
num= roman_Number (num,5,'v');
if(num>=1)
num= roman_Number (num,1,'i');
return 0;
}
int roman_Number (int num,int x_Num,char c) {
if(num==9){
cout <<"ix";
return 0;
}
if(num==4){
cout <<"iv";
return 0;
}
while(num>= x_Num ){
cout<<c;
num=num-x_Num;
}
return num;
}4. By Pure
Made by Pure. Simple Program to convert decimal to roman. ( Source )
#include <iostream>
#include <string>
using namespace std;
int main() {
double num;
string roman;
string hundreds;
string tens;
string ones;
cout << "enter your decimal based number that will convert to roman numerals" << endl;
cin >> num;
if (num > 0 && num < 200) {
if (num >=100 && num <=199){
hundreds = "C";
num = num - 100;
}
if (num >= 90 && num <=99) {
tens = "XC";
num = num - 90;
}
if (num >= 80 && num <=89) {
tens = "LXXX";
num = num - 80;
}
if (num >= 70 && num <= 79) {
tens = "LXX";
num = num - 70;
}
if (num >= 60 && num <= 69) {
tens = "LX";
num = num - 60;
}
if (num >= 50 && num <= 59) {
tens = "L";
num = num - 50;
}
if (num >= 40 && num <= 49) {
tens = "XL";
num = num - 40;
}
if (num >= 30 && num <= 39) {
tens = "XXX";
num = num - 30;
}
if (num >= 20 && num <= 29) {
tens = "XX";
num = num - 20;
}
if (num >= 10 && num <= 19) {
tens = "X";
num = num - 10;
}
if (num == 9) {
ones = "IX";
num = num - 9;
}
if (num == 8) {
ones = "VIII";
num = num - 8;
}
if (num == 7) {
ones = "VII";
num = num - 7;
}
if (num == 6) {
ones = "VI";
num = num - 6;
}
if (num == 5) {
ones = "V";
num = num - 5;
}
if (num == 4) {
ones = "IV";
num = num - 4;
}
if (num == 3) {
ones = "III";
num = num - 3;
}
if (num == 2) {
ones = "II";
num = num - 2;
}
if (num == 1) {
ones = "I";
num = num - 1;
}
}
else
{
cout << "Invalid." << endl;
}
roman = hundreds + tens + ones;
cout << roman << endl;
return 0;
}5. By Roman
Made by Roman. ( Source )
#include <iostream>
#include <string>
using namespace std;
void pasaje(int fila, int num){
string f[4][3] = {
{"M","",""},
{"C","D","M"},
{"X","L","C"},
{"I","V","X"}
};
string l1 = f[fila][0];
string l2 = f[fila][1];
string l3 = f[fila][2];
string k[10] = {
"",
l1,
l1 + l1,
l1 + l1 + l1,
l1 + l2,
l2,
l2 + l1,
l2 + l1 + l1,
l2 + l1 + l1 + l1,
l1 + l3
};
cout << k[num];
}
int main() {
int num;
cin >> num;
int m = num/1000;
int c = (num-m*1000)/100;
int d = (num-m*1000-c*100)/10;
int u = (num-m*1000-c*100-d*10);
if (num>0 && num<=3999){
cout << num << " equivale a " ;
pasaje (0,m);
pasaje (1,c);
pasaje (2,d);
pasaje (3,u);
cout << " en numeros romanos." << endl;
}
else (cout << "No existe tal numero en numeracion romana" <<endl);
return 0;
}6. By Roman 2.0
Made by Roman 2.0. ( Source )
#include <iostream>
#include <string>
using namespace std;
void pasaje(int dig, int num){
string l1;
string l2;
string l3;
switch (dig){
case 4:
l1 = "M";
break;
case 3:
l1 = "C";
l2 = "D";
l3 = "M";
break;
case 2:
l1 = "X";
l2 = "L";
l3 = "C";
break;
case 1:
l1 = "I";
l2 = "V";
l3 = "X";
break;
}
switch (num){
case 0:
cout << "";
break;
case 1:
cout << l1;
break;
case 2:
cout << l1 << l1;
break;
case 3:
cout << l1 << l1 << l1;
break;
case 4:
cout << l1 << l2;
break;
case 5:
cout << l2;
break;
case 6:
cout << l2 << l1;
break;
case 7:
cout << l2 << l1 << l1;
break;
case 8:
cout << l2 << l1 << l1 << l1;
break;
case 9:
cout << l1 << l3;
break;
}
}
int main() {
int num;
cin >> num;
int m = num/1000;
int c = (num-m*1000)/100;
int d = (num-m*1000-c*100)/10;
int u = (num-m*1000-c*100-d*10);
if (num>0 && num<=3999){
cout << num << " equivale a " ;
pasaje (4,m);
pasaje (3,c);
pasaje (2,d);
pasaje (1,u);
cout << " en numeros romanos." << endl;
}
else (cout << "No existe tal numero en numeracion romana" <<endl);
return 0;
}7. By voki
Made by voki. ( Source )
#include <iostream>
#include <string>
#include <vector>
//predefinitions of functions
void breakTheNumber(int);
int getOnes(int);
int getTens(int);
int getHundreds(int);
int getThousends(int);
int main()
{
std::cout << "Decimal to Roman number conventor. Enter a number up to 9,999 to convert.\n";
int userNumber{ 0 };
char answer{ 'n' };
do {
std::cout << "\nEnter your number: \t";
std::cin >> userNumber;
//send the number to function to break it to ones, tens, hundreds, thousends
breakTheNumber(userNumber);
std::cout << "\nWould you like to try another number? (y/n) \n";
std::cin >> answer;
} while (answer == 'y');
return 0;
}
void breakTheNumber(int num)
{
//vectors of strings with roman numbers
std::vector<std::string> ones{ "", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX" };
std::vector<std::string> tens {"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"};
std::vector<std::string> hundreds {"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM" };
std::vector<std::string> thousends {"", "M", "MM", "MMM", "MMMM", "MMMMM", "MMMMMM", "MMMMMMMM", "MMMMMMMMM", "MMMMMMMMMM" };
//call functions to get tens, hundreds...
int onesNum{ getOnes(num) };
int tensNum{ getTens(num) };
int hundredsNum{ getHundreds(num) };
int thousendsNum{ getThousends(num) };
std::cout << "Your number(" << num << ") is in Roman: " << thousends[thousendsNum];
std::cout << hundreds[hundredsNum] << tens[tensNum] << ones[onesNum] << std::endl;
}
int getOnes(int num)
{
return(num % 10);
}
int getTens(int num)
{
//check if num bigger than 10
if (num >= 10)
{
//need to divide by ten to get tens and get modulus of 10 to get only tens, not hundreds...
int tens{ num / 10 };
return (tens % 10);
}
else
return 0;
}
int getHundreds(int num)
{
if (num >= 100)
{
int hundreds{ num / 100 };
return (hundreds % 10);
}
else
return 0;
}
int getThousends(int num)
{
if (num >= 1000)
{
int thousend{ num / 1000 };
return (thousend % 10);
}
else
return 0;
}8. By MO AHSAN AHMAD
Made by MO AHSAN AHMAD. ( Source )
#include<iostream>
#include<stdio.h>
using namespace std;
int main()
{
int num;
cout<<"\nenter a number : ";
cin>>num;
cout<<"\nRoman symbol is : ";
while(num!=0)
{
if(num>=1000)
{
cout<<"m";
num-=1000;
}
else if(num>=900)
{
cout<<"cm";
num-=900;
}
else if(num>=500)
{
cout<<"d";
num-=500;
}
else if(num>=400)
{
cout<<"cd";
num-=400;
}
else if(num>=100)
{
cout<<"c";
num-=100;
}
else if(num>=90)
{
cout<<"xc";
num-=90;
}
else if(num>=50)
{
cout<<"l";
num-=50;
}
else if(num>=40)
{
cout<<"xl";
num-=40;
}
else if(num>=10)
{
cout<<"x";
num-=10;
}
else if(num>=9)
{
cout<<"ix";
num-=9;
}
else if(num>=5)
{
cout<<"v";
num-=5;
}
else if(num>=4)
{
cout<<"iv";
num-=4;
}
else if(num>=1)
{
cout<<"i";
num-=1;
}
}
return 0;
}9. By Pure
Made by Pure. ( Source )
#include <iostream>
#include <string>
using namespace std;
int main() {
int decbaseNum;
int romanNum;
cout << "This program converts your Decimal Based Numbers to Roman Numerals" << endl;
cout << "Please enter a number from 1 to 99" << endl;
cin >> decbaseNum;
cout << "Your input was " << decbaseNum << endl;
cout << decbaseNum << " is converted to " << endl;
switch (decbaseNum)
{
case 1: cout << "I";
break;
case 2: cout << "II";
break;
case 3: cout << "III";
break;
case 4: cout << "IV";
break;
case 5: cout << "V";
break;
case 6: cout << "VI";
break;
case 7: cout << "VII";
break;
case 8: cout << "VIII";
break;
case 9: cout << "IX";
break;
case 10: cout << "X";
break;
case 11: cout << "XI";
break;
case 12: cout << "XII";
break;
case 13: cout << "XIII";
break;
case 14: cout << "XIV";
break;
case 15: cout << "XV";
break;
case 16: cout << "XVI";
break;
case 17: cout << "XVII";
break;
case 18: cout << "XVIII";
break;
case 19: cout << "XIX";
break;
case 20: cout << "XX";
break;
case 21: cout << "XXI";
break;
case 22: cout << "XXII";
break;
case 23: cout << "XXIII";
break;
case 24: cout << "XXIV";
break;
case 25: cout << "XXV";
break;
case 26: cout << "XXVI";
break;
case 27: cout << "XXVII";
break;
case 28: cout << "XXVIII";
break;
case 29: cout << "XXIX";
break;
case 30: cout << "XXX";
break;
case 31: cout << "XXXI";
break;
case 32: cout << "XXXII";
break;
case 33: cout << "XXXIII";
break;
case 34: cout << "XXXIV";
break;
case 35: cout << "XXXV";
break;
case 36: cout << "XXXVI";
break;
case 37: cout << "XXXVII";
break;
case 38: cout << "XXXVIII";
break;
case 39: cout << "XXXIX";
break;
case 40: cout << "XL";
break;
case 41: cout << "XLI";
break;
case 42: cout << "XLII";
break;
case 43: cout << "XLIII";
break;
case 44: cout << "XLIV";
break;
case 45: cout << "XLV";
break;
case 46: cout << "XLVI";
break;
case 47: cout << "XLVII";
break;
case 48: cout << "XLVIII";
break;
case 49: cout << "XLIX";
break;
case 50: cout << "L";
break;
case 51: cout << "LI";
break;
case 52: cout << "LII";
break;
case 53: cout << "LIII";
break;
case 54: cout << "LIV";
break;
case 55: cout << "LV";
break;
case 56: cout << "LVI";
break;
case 57: cout << "LVII";
break;
case 58: cout << "LVIII";
break;
case 59: cout << "LIX";
break;
case 60: cout << "LX";
break;
case 61: cout << "LXI";
break;
case 62: cout << "LXII";
break;
case 63: cout << "LXIII";
break;
case 64: cout << "LXIV";
break;
case 65: cout << "LXV";
break;
case 66: cout << "LXVI";
break;
case 67: cout << "LXVII";
break;
case 68: cout << "LXVIII";
break;
case 69: cout << "LXIX";
break;
case 70: cout << "LXX";
break;
case 71: cout << "LXXI";
break;
case 72: cout << "LXXII";
break;
case 73: cout << "LXXIII";
break;
case 74: cout << "LXXIV";
break;
case 75: cout << "LXXV";
break;
case 76: cout << "LXXVI";
break;
case 77: cout << "LXXVII";
break;
case 78: cout << "LXXVIII";
break;
case 79: cout << "LXXIX";
break;
case 80: cout << "LXXX";
break;
case 81: cout << "LXXXI";
break;
case 82: cout << "LXXXII";
break;
case 83: cout << "LXXXIII";
break;
case 84: cout << "LXXXIV";
break;
case 85: cout << "LXXXV";
break;
case 86: cout << "LXXXVI";
break;
case 87: cout << "LXXXVII";
break;
case 88: cout << "LXXXVIII";
break;
case 89: cout << "LXXXIX";
break;
case 90: cout << "XC";
break;
case 91: cout << "XCI";
break;
case 92: cout << "XCII";
break;
case 93: cout << "XCIII";
break;
case 94: cout << "XCIV";
break;
case 95: cout << "XCV";
break;
case 96: cout << "XCVI";
break;
case 97: cout << "XCVII";
break;
case 98: cout << "XCVIII";
break;
case 99: cout << "XCIX";
break;
default: cout << "You didn't enter a number from 1-99";
}
return 0;
}10. By Ella
Made by Ella. C++ Program for Converting Decimal numbers to Roman Numerals. ( Source )
#include <iostream>
using namespace std;
int main() {
int var,nx,nv,ni,i;
//variable, no of X, no of V, no of I
cout<<"\nEnter no to be converted: \n";
cout<<"(Only Decimal Numbers less than 50)";
cin>>var;
cout<<endl;
nx=var/10;
for(i=0;i<nx;i++)
cout<<'X';
var%=10;
if(var==9){
cout<<"IX";
return 0;
}
nv=var/5;
for(i=0;i<nv;i++)
cout<<"V";
var%=5;
if(var==4){
cout<<"IV";
return 0;
}
ni=var;
for(i=0;i<ni;i++)
cout<<"I";
return 0;
}11. By Fritz Bryan
Made by Fritz Bryan. ( Source )
#include <iostream>
using namespace std;
int main() {
char val[100];
int x, y=0;
cout << "Enter a number: ";
cin >> x;
while(x!=0) {
if(x>4000) {
cout << "Number is too large.";
break;
}
else if(x>=1000) {
x = x-1000;
val[y] = 'M';
y++;
}
else if (x>=900) {
x = x-900;
val[y] = 'C';
y++;
val[y] = 'M';
y++;
}
else if(x>=500) {
x = x-500;
val[y] = 'D';
y++;
}
else if(x>=400) {
x = x-400;
val[y] = 'C';
y++;
val[y] = 'D';
y++;
}
else if(x>=100) {
x = x-100;
val[y] = 'C';
y++;
}
else if(x>=90) {
x = x-90;
val[y] = 'X';
y++;
val[y] = 'C';
y++;
}
else if(x>=50) {
x = x-50;
val[y] = 'L';
y++;
}
else if(x>=40) {
x = x-40;
val[y] = 'X';
y++;
val[y] = 'L';
y++;
}
else if(x>=10) {
x = x-10;
val[y] = 'X';
y++;
}
else if(x==9) {
x = x-9;
val[y] = 'I';
y++;
val[y] = 'X';
y++;
}
else if(x>=5) {
x = x-5;
val[y] = 'V';
y++;
}
else if(x>=4) {
x = x-4;
val[y] = 'I';
y++;
val[y] = 'V';
y++;
}
else if (x>=1) {
x--;
val[y] = 'I';
y++;
}
}
if(x<4000) {
cout << "Roman Numeral: " << val;
}
return 0;
}
12. By JulioC OG
Made by JulioC OG. Enter an int number between 1-3999 and this code output a string with the roman equivalent. ( Source )
#include <iostream>
#include "string"
using namespace std;
const string romAns[4][10] = {
{ "", "M", "MM", "MMM" },
{ "", "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" }
};
int main() {
string roman = "";
unsigned int romanArr[4] = {0,0,0,0};
unsigned int lremindr = 0;
unsigned int denom = 1;
cin >> lremindr;
if( lremindr > 0 && lremindr < 4000 ){
for(int i = 0; i < 4; i++){
switch (i){
case(0): denom = 1000; break;
case(1): denom = 100; break;
case(2): denom = 10; break;
case(3): denom = 1; break;
}
romanArr[i] = lremindr / denom;
lremindr %= denom;
}
for(int i = 0; i < 4; i++){
roman += romAns[i][romanArr[i]];
}
}else{ roman = "Out of boundaries!"; }
cout << roman;
return 0;
}13. By Pasquale Perrone
Made by Pasquale Perrone. ( Source )
#include <iostream>
using namespace std;
int main() {
int n; char l;
cin >> n;
while(n){
if(n>=1000){
cout << "M";
n-=1000;
}
else if(n>=500){
if(n>=900){
cout << "CM";
n-=900;
}
else{
cout << "D";
n-=500;
}
}
else if(n>=100){
if(n>=400){
cout << "CD";
n-=400;
}
else{
cout << "C";
n-=100;
}
}
else if(n>=50){
if(n>=90){
cout << "XC";
n-=90;
}
else{
cout << "L";
n-=50;
}
}
else if(n>=10){
if(n>=40){
cout << "XL";
n-=40;
}
else{
cout << "X";
n-=10;
}
}
else if(n>=5){
if(n==9){
cout << "IX";
n-=9;
}
else{
cout << "V";
n-=5;
}
}
else{
if(n==4){
cout << "IV";
n-=4;
}
else{
cout << "I";
n-=1;
}
}
}
return 0;
}14. By sparsh
Made by sparsh. ( Source )
#include <bits/stdc++.h>
using namespace std;
// Function to calculate roman equivalent
string intToRoman(int num)
{
// storing roman values of digits from 0-9
// when placed at different places
string m[] = {"", "M", "MM", "MMM"};
string c[] = {"", "C", "CC", "CCC", "CD", "D",
"DC", "DCC", "DCCC", "CM"};
string x[] = {"", "X", "XX", "XXX", "XL", "L",
"LX", "LXX", "LXXX", "XC"};
string i[] = {"", "I", "II", "III", "IV", "V",
"VI", "VII", "VIII", "IX"};
// Converting to roman
string thousands = m[num/1000];
string hundereds = c[(num%1000)/100];
string tens = x[(num%100)/10];
string ones = i[num%10];
string ans = thousands + hundereds + tens + ones;
return ans;
}
// Driver program to test above function
int main()
{
int number = 3549;
cout << intToRoman(number);
return 0;
}15. By Mr. Rahul
Made by Mr. Rahul. ( Source )
// C++ Program to convert decimal number to roman
#include <iostream>
#include <bits/stdc++.h>
using namespace std;
// Function to convert decimal to Roman Numerals
void printRoman(int n)
{
int num[] = {1,4,5,9,10,40,50,90,100,400,500,900,1000};
string sym[] = {"I","IV","V","IX","X","XL","L","XC","C","CD","D","CM","M"};
int i=12;
while(n>0)
{
int div = n/num[i];
n = n%num[i];
while(div--)
{
cout<<sym[i];
}
i--;
}
}
//Driver program
int main()
{
int n;
cin >> n;
printRoman(n);
return 0;
}16. By Andrea Leoni
Made by Andrea Leoni. Program that gets an int number (between 1 and 3000) and converts it into the corresponding roman number. ( Source )
#include <iostream>
using namespace std;
// function that converts the signle digit to roman
void stampch(char,char,char,int);
int main()
{
cout << "Enter an integer number (between 1 and 3000): ";
int num;
cin >> num;
cout << endl << num << " in roman numbers is ";
int num0 = num;
// THOUSANDS in roman representation
if(num/1000>0) {
num /= 1000;
for(int i=0; i<num; ++i)
cout << 'M';
num = num0%1000;
}
// HUNDREDS in roman representation
if(num/100>0) {
num /= 100;
stampch('C','D','M',num);
num = num0%100;
}
// TENS in roman representation
if(num/10>0) {
num /= 10;
stampch('X','L','C',num);
num = num0%10;
}
// ONES in roman representation
stampch('I','V','X',num);
cout << endl;
return 0;
}
void stampch(char one, char five, char ten, int nch) {
if(nch==4)
cout << one << five; // one << five
else
if(nch==9)
cout << one << ten; // one << ten
else {
if(nch>=5)
cout << five; // five
for(int i=0; i<(nch%5); ++i)
cout << one; //one
}
}