Java 提款卡密碼

題目: 提款卡密碼

import java.util.Scanner;
import java.lang.Math;

public class ATMCard{
    public static Scanner sc = new Scanner(System.in);
    public static String str;
    public static int length,a,b,i;
 
    public static void main(String args[]){
        while(sc.hasNext()){
            str = sc.nextLine();
   
            length = str.length();
            a = (int)(str.charAt(0));
            i = 0;
            while(++i < length){
                b = (int)(str.charAt(i));
                System.out.print(Math.abs(a - b));
                a = b;
            }
            System.out.println();
        }
    }
}