//C++ Program to convert Roman number string to integer. int romanToInt(char c) { switch (c) { case 'I': return 1; case 'V': return 5; case 'X': return 10; case 'L': return 50; case 'C': return 100; case 'D': return 500; case 'M': return 1000; default: return 0; } } int convertRomanToInt(const string & roman) { int number = 0; int size = roman.size(); for (int i = 0; i < size; i++) { if ((i < (size - 1)) && romanToInt(roman[i]) < romanToInt(roman[i + 1])) { number -= romanToInt(roman[i]); } else { number += romanToInt(roman[i]); } } return number ; }