java - 为什么这个 while 循环在 roll and roll 2 之后不停止？

Question

我创建了一个简单的掷骰子程序。但是while循环不会在什么时候停止roll1 和 roll2 相等。总数并没有加起来。程序运行无限次，我必须停止它。请帮忙。

输出:

Roll #1: 1
Roll #2: 2
Total is : 3
Roll #1: 4
Roll #2: 1
Total is : 3
Roll #1: 4
Roll #2: 4
Total is : 3
Roll #1: 2
Roll #2: 5
Total is : 3
Roll #1: 4
Roll #2: 4
Total is : 3
Roll #1: 0
Roll #2: 2
Total is : 3
Roll #1: 4
Roll #2: 3
Total is : 3

源代码:

import java.util.Scanner;
import java.util.Random;

public class App1
{
    public static void main( String[] args )
    {
        Random r = new Random();

        int roll1 = 1+ r.nextInt(6);
        int roll2 = 1+ r.nextInt(6);
        int total = roll1 + roll2;

        System.out.println("Heres comes the dice!");
        System.out.println();


        while ( roll1 != roll2 )
        {
            System.out.println("Roll #1: "  + roll1);
            System.out.println("Roll #2: "  + roll2);
            System.out.println("Total is : " + total );

        }
        System.out.println("Roll #1: "  + roll1);
        System.out.println("Roll #2: "  + roll2);
        System.out.println("Total is : " + total );


    }
 }

Answer 1

因为在 while 循环中你没有得到新的值:

while ( roll1 != roll2 )
{
    System.out.println("Roll #1: "  + roll1);
    System.out.println("Roll #2: "  + roll2);
    System.out.println("Total is : " + total );

    roll1 = 1+ r.nextInt(6);
    roll2 = 1+ r.nextInt(6);
    total = roll1 + roll2;
}

第一次进入 while 循环 roll1 和 roll2 有一个随机值，但是如果你不使用我添加的新行更改这个值，那么您将始终循环到您拥有的相同值。

关于 roll1 和 roll2 值的变化，这对我来说没有意义，在我的电脑上你的代码结果是:

启动 1

Total is : 7
Roll #1: 1
Roll #2: 6
Total is : 7
Roll #1: 1
Roll #2: 6
Total is : 7
Roll #1: 1
Roll #2: 6
Total is : 7

启动 2

Total is : 8
Roll #1: 5
Roll #2: 3
Total is : 8
Roll #1: 5
Roll #2: 3
Total is : 8
Roll #1: 5
Roll #2: 3
Total is : 8