# Decimal to roman numeral converter in c++

C++ program for Decimal to roman numeral converter. Here mentioned other language solution.

``````// Include header file
#include <iostream>
#include <string>
#include <vector>

//  stdc++11 program for
//  Conversion from Decimal to roman number
class Perform
{
// Display roman value of n
public:
static void result(int n)
{
switch (n){
// Test Cases
case 1:
std::cout << "I";
break;
case 4:
std::cout << "IV";
break;
case 5:
std::cout << "V";
break;
case 9:
std::cout << "IX";
break;
case 10:
std::cout << "X";
break;
case 40:
std::cout << "XL";
break;
case 50:
std::cout << "L";
break;
case 90:
std::cout << "XC";
break;
case 100:
std::cout << "C";
break;
case 400:
std::cout << "CD";
break;
case 500:
std::cout << "D";
break;
case 900:
std::cout << "DM";
break;
case 1000:
std::cout << "M";
break;
}
}
static long select(long number,
std::vector<int> collection,
int size)
{
int n = 1;
int i = 0;
for (
i = 0; i < size; ++i)
{
if (number >= collection[i])
{
n = collection[i];
}
else
{
break;
}
}
Perform::result(n);
// Reduce the value of number
return number - n;
}
static void romanNo(long number)
{
if (number <= 0)
{
// When is not a natural number
return;
}
// Base case collection
// We used an vector you can do with an array
std::vector<int> collection{1, 4, 5, 9, 10,
40, 50, 90, 100, 400, 500, 900, 1000};
// Get the size of collection
int size = collection.size();
std::cout << " " + std::to_string(number) + " : ";
while (number > 0)
{
number = Perform::select(number, collection, size);
}
std::cout << std::endl;
}

};
int main(int argc, char **argv){
// Test Case
Perform::romanNo(10);
Perform::romanNo(18);
Perform::romanNo(189);
Perform::romanNo(604);
Perform::romanNo(982);
Perform::romanNo(3000);
return 0;
};``````

Output

`````` 10 : X
18 : XVIII
189 : CLXXXIX
604 : DCIV
982 : DMLXXXII
3000 : MMM``````

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