Roman numerals

Roman numerals

Convert a Roman numeral to an int. The symbols are I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Usually you add, but when a smaller symbol sits before a larger one you subtract it: IV is 4, IX is 9, MCMXCIV is 1994. Scanning from right to left makes the subtract rule easy — subtract any symbol smaller than the one to its right.