Something

import java.util.Scanner;

public class Rooma {

	private static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {
		System.out.print("Syötä roomalainen luku: ");
		String kirjaimet = lueString();
		int i = 0;
		int summa = 0;
		while (i < kirjaimet.length()) {
			switch ( kirjaimet.charAt(i) ) {
			case 'M':
				summa = summa + 1000;
				break;
			case 'D':
				summa = summa + 500;
				break;
			case 'C':
				summa = summa + 100;
				break;
			case 'L':
				summa = summa + 50;
				break;
			case 'X':
				summa = summa + 10;
				break;
			case 'V':
				summa = summa + 5;
				break;
			case 'I':
				summa = summa + 1;
				break;
			}
			i = i + 1;
		}
		System.out.println("Lukusi " + kirjaimet + " on " + summa + ".");
	}

	public static String lueString() {
		String aString = sc.next();
		return aString;
	}
}