exercise7_7.java

Introduction to java programming 一书中所有编程练习部分的源码

public class Exercise7_7 {
    public static void main(String[] args) {
        System.out.println(parseHex("10"));
        System.out.println(parseHex("ABC"));
        System.out.println(parseHex("10A"));
    }
    
    public static int parseHex(String hexString) {
        int value = convertHexToDec(hexString.charAt(0));
        for (int i = 1; i < hexString.length(); i++) {
            value = value * 16 + hexString.charAt(i) - '0';
        }
        
        return value;
    }
    
    static int convertHexToDec(char ch) {
        if (ch == 'A')
            return 10;
        else if (ch == 'B')
            return 11;
        else if (ch == 'C')
            return 12;
        else if (ch == 'D')
            return 13;
        else if (ch == 'E')
            return 14;
        else if (ch == 'F')
            return 15;
        
        return ch - '0';
    }
}