input only roman numerals

[axel609]

how do i program so that the user can only input roman Numerals(MXXL)

  
#include <iostream>
#include <string>
#include <cctype>
#include <iomanip>
using namespace std;

bool checker(string roman);



int main()
{
	string roman;
	char goAgain;
	int value;
	
do
{
	cout << "Please enter the Roman Numeral to convert : ";
	cin >> roman;
	
	bool checker(string roman);
 
 
 cout << "Roman Number " << roman << " equals " <<endl;
 cout << "Want to convert Roman NUmeral again(Y or N)";
 cin >> goAgain;

while(toupper(goAgain) !='Y' && toupper(goAgain) !='N')
{
  cout << "please enter Y or N: ";
  cin >> goAgain;
}
	
}while(toupper(goAgain) =='Y');

return 0;
}


bool checker(string roman)
{

   
}

[Duthomhas]

A roman number can only be composed of the letters "IVXLCDM" (either majuscule or miniscule). So checker() should see if there are any letters except those in the string.

There is a special case: zero is represented either with "N" or "NULLA". You might get bonus points for checking if your string is equal to either of those.

Hope this helps.

[axel609]

sorry but this doesn't really help me