Here you can find the source of toDigit(char c)
private static int toDigit(char c)
//package com.java2s; //License from project: Open Source License public class Main { private static int toDigit(char c) { if (c >= '0' && c <= '9') return c - '0'; if (c >= 'a' && c <= 'f') return c - 'a' + 10; if (c >= 'A' && c <= 'F') return c - 'A' + 10; return -1; }//w w w .j av a 2 s .com }