无效并返回Java-何时使用 [英] Void and return in Java - when to use

问题描述

我对虚无和回报有些困惑".通常，我知道在方法中使用void而不返回任何内容，而当我想将某些内容返回给调用代码时，则在方法中使用return.

I have some "confusion" about void and return. In general, I understand void is used in methods without returning anything, and return is used in methods when I want to return something to the calling code.

但是在下面的代码中，我可以同时使用两者，而我的问题是，使用哪个?以及如何确定?与性能有关吗?

But in the following code, I can use both, and my question is, which one to use? And how to determine? Is it about performance?

通常，在两种情况下我的结果都是相同的.

Normally, I have the same results in both cases.

public class Calc {
    private double number;

    Calc (double n)
    {
        number = n;
    }

    public void add(double n)
    {
        number += n;
    }   

    public double add1(double n)
    {
        return number = number +  n;
    }
}

谢谢！

推荐答案

此方法:

public void add(double n)
{
   number += n;
} 

您更改了 number 的内部状态，但是此方法的调用者不知道 number 的最终值.

You change the internal state of number but the caller of this method doesn't know the final value of number.

在下面的方法中，您将提示呼叫者 number 的最终值.

In the below method, you are intimating the caller the final value of number.

public double add1(double n)
{
   return number = number +  n;
}

我建议保留一个单独的 getNumber() getter方法.

I would suggest to keep a separate getNumber() getter method.

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