RomanNumeralConverter

import java.util.HashMap;

/*
 * RomanNumeralConverter converts numbers from the Roman Numeral System to
 * regular base-10 numbers and back again.
 * @author hypesystem
 * @version 2012-02-16
 */
public class RomanNumeralConverter {
    private HashMap<Character,Integer> values;

    public RomanNumeralConverter() {
        values = new HashMap<Character,Integer>();

        values.put('I',1);
        values.put('V',5);
        values.put('X',10);
        values.put('L',50);
    }

    public int fromRoman(String s) {
        int length = s.length();
        int value = 0;
        for(int pos = 0; pos < length; pos++) {
            if(pos < (s.length() - 1) && values.get(s.charAt(pos)) < values.get(s.charAt(pos + 1))) {
                value += (values.get(s.charAt(pos + 1)) - values.get(s.charAt(pos))); pos++;
            }
            else value += values.get(s.charAt(pos));
        }
        return value;
    }

    public static void main(String[] args) {
        RomanNumeralConverter rom = new RomanNumeralConverter();
        rom.test("I");
        rom.test("II");
        rom.test("III");
        rom.test("IV");
        rom.test("V");
        rom.test("VI");
        rom.test("VII");
        rom.test("XVII");
        rom.test("XLIV");
    }

    private void test(String s) {
        StdOut.println(s+" "+fromRoman(s));
    }
}