java---抽奖游戏

package com.farsight.session5;

import java.util.Scanner;

public class Choujiang {
public static void main(String[] args) {
while (true) {
System.out.println("请输入您手机号的后四位：");
Scanner sc = new Scanner(System.in);
int num = sc.nextInt();
int gewei = num % 10;
int shiwei = num / 10 % 10;
int baiwei = num / 100 % 10;
int qianwei = num / 1000;
int add = gewei + shiwei + baiwei + qianwei;
if (add > 20) {
System.err.println("恭喜您！手机尾号为" + num + "获得ipad一台！\n");
} else {
System.out.println("您的手机号后四位是" + num);
System.err.println("很遗憾，您没中奖。\n");
}
}
}
}