关于结束问题 [英] About the while ending problems

问题描述

我想知道为什么这个永远不会结束，即使布尔类型的返回是真的。



这是代码：

I want to know why this never ending even the boolean type return is true.

Here is the code:

public class lotto {
	
	public static void main(String[] args){
		Random rand = new Random();
		
		boolean result = seven(rand);
		
		while(result == false){
			System.out.println("");
			seven(rand);
		}
	
		
	}
	
	public static boolean seven(Random rand){
	
		
		for(int i =1; i<=10; i++){
			
			int num = rand.nextInt(30)+1;
			
			System.out.print(num + " ");
			
			if(num == 7){
				return true;		
			}
			
		}
		return false;
	
				
		
		
	}

}

我尝试了什么：



我尝试使用if / else的方式不同，但如果/ else它只打印两行代码，同时将打印无限的代码行。在此先感谢!!!

What I have tried:

I try different way by using if/else, but if/else it only print two line of code, while will print infinite line of code. Thanks in advance!!!

推荐答案

因为你从未在<$ c $里面分配结果一个新值c> while 循环。 结果以虚假值开始，永远不会获得新值。



它应该是：

Because you never assign result a new value inside the while loop. result starts out with a false value and never gets a new value.

It should be:

while (result == false) {
    System.out.println("");
    result = seven(rand);
}

因为你在循环内部永远不会更新结果。

您应该尝试调试器，它允许您在代码执行时检查变量。



有一个工具可以让你看到你的代码在做什么，它的名字是调试器。它也是一个很好的学习工具，因为它向你展示了现实，你可以看到哪种期望与现实相符。

当你不明白你的代码在做什么或为什么它做它做的时候，答案就是答案是调试器。

使用调试器查看代码正在执行的操作。只需设置断点并查看代码执行情况，调试器允许您逐行执行第1行并在执行时检查变量。



调试器 - 维基百科，免费的百科全书 [ ^ ]

http://docs.oracle.com/javase/7/docs/technotes/tools/windows/jdb.html [ ^ ]

https://www.jetbrains.com/idea/help/debugging-your-first-java-application.html [ ^ ]

调试器在这里向您展示你的代码正在做，你的任务是与它应该做的事情进行比较。

调试器中没有魔法，它没有找到错误，它只是帮助你。当代码没有达到预期的效果时，你就会接近一个错误。

Because you never update result when inside the loop.
You should try the debugger, it allow you to inspect variables as your code execute.

There is a tool that allow you to see what your code is doing, its name is debugger. It is also a great learning tool because it show you reality and you can see which expectation match reality.
When you don't understand what your code is doing or why it does what it does, the answer is debugger.
Use the debugger to see what your code is doing. Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.

Debugger - Wikipedia, the free encyclopedia[^]
http://docs.oracle.com/javase/7/docs/technotes/tools/windows/jdb.html[^]
https://www.jetbrains.com/idea/help/debugging-your-first-java-application.html[^]
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't find bugs, it just help you to. When the code don't do what is expected, you are close to a bug.

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