Question

I am writing C++ code, and I need help for this.

Create a program that will convert a decimal value into Roman numeral, and output the result. The program will ask for an integer input, assume all inputs are valid, and the program should not end unless the user tells you to.

C++ code.

Answer 1

ANSWER: Here I am giving you the code and output if you have problem then comment or like it .

CODE:

#include <iostream>
using namespace std;
void predigit(char num1, char num2);
void postdigit(char c, int n);

char romanval[1000];
int i = 0;
int main()
{
int j;
long number;

while(1){
cout<<" Enter the number or enter 0 or negative number to exit: ";
cin>>number;

if (number <= 0)
{
cout<<"Invalid number";
return 0;
}
while (number != 0)
{
if (number >= 1000)
{
postdigit('M', number / 1000);
number = number - (number / 1000) * 1000;
}
else if (number >= 500)
{
if (number < (500 + 4 * 100))
{
postdigit('D', number / 500);
number = number - (number / 500) * 500;
}
else
{
predigit('C','M');
number = number - (1000-100);
}
}
else if (number >= 100)
{
if (number < (100 + 3 * 100))
{
postdigit('C', number / 100);
number = number - (number / 100) * 100;
}
else
{
predigit('L', 'D');
number = number - (500 - 100);
}
}
else if (number >= 50 )
{
if (number < (50 + 4 * 10))
{
postdigit('L', number / 50);
number = number - (number / 50) * 50;
}
else
{
predigit('X','C');
number = number - (100-10);
}
}
else if (number >= 10)
{
if (number < (10 + 3 * 10))
{
postdigit('X', number / 10);
number = number - (number / 10) * 10;
}
else
{
predigit('X','L');
number = number - (50 - 10);
}
}
else if (number >= 5)
{
if (number < (5 + 4 * 1))
{
postdigit('V', number / 5);
number = number - (number / 5) * 5;
}
else
{
predigit('I', 'X');
number = number - (10 - 1);
}
}
else if (number >= 1)
{
if (number < 4)
{
postdigit('I', number / 1);
number = number - (number / 1) * 1;
}
else
{
predigit('I', 'V');
number = number - (5 - 1);
}
}
}
cout<<"Roman number is: ";
for(j = 0; j < i; j++)
cout<< romanval[j];
}
  
return 0;
}

void predigit(char num1, char num2)
{
romanval[i++] = num1;
romanval[i++] = num2;
}

void postdigit(char c, int n)
{
int j;
for (j = 0; j < n; j++)
romanval[i++] = c;
}

OUTPUT: