Java convert letter to number

/**
 * @author lautturi.com 
 * Java example: letter to number
 */


import java.util.*;

public class Lautturi {

	public static void main(String[] args) {
		
		char ch = 'd';
		int number = ch - 'a' + 1;
		
		System.out.println("Character:"+ch+" Number:"+number);

	}
}

output:

Character:d Number:4