Here you can find the source of convertCharToInt(char input)
public static int convertCharToInt(char input)
//package com.java2s; public class Main { public static int convertCharToInt(char input) { if ((int) input >= (int) 'A') { return ((int) input - (int) 'A' + 10); } else {//from w w w . j av a 2 s .com return ((int) input - (int) '0'); } } }