return in for 循环或外循环 [英] return in for loop or outside loop

问题描述

今天，有人提醒我在 Java 中错误使用了 return 关键字.我编写了一个简单的 for 循环来验证数组中是否存在某些内容.假设 array 是一个长度为 n 的数组，这是我的代码:

Today, someone attended me to bad use of the return keyword in Java. I had written a simple for loop to validate that something is in an array. Supposing array is an array of length n, this was my code:

for (int i = 0; i < array.length; ++i) {
    if (array[i] == valueToFind) {
        return true;
    }
}
return false;

现在有人告诉我，这不是很好的编程，因为我在循环中使用了 return 语句，这会导致垃圾收集发生故障.因此，更好的代码应该是:

Now someone told me that this is not very good programming because I use the return statement inside a loop and this would cause garbage collection to malfunction. Therefore, better code would be:

int i = 0;
while (i < array.length && array[i] != valueToFind) {
    ++i;
}
return i != array.length;

问题是我无法正确解释为什么第一个 for 循环不是一个好习惯.有人可以给我解释一下吗?

The problem is that I can't come up with a proper explenation of why the first for loop isn't a good practice. Can somebody give me an explanation?

推荐答案

现在有人告诉我，这不是很好的编程，因为我在循环中使用了 return 语句，这会导致垃圾收集发生故障.

Now someone told me that this is not very good programming because I use the return statement inside a loop and this would cause garbage collection to malfunction.

这是不正确的，并建议您应该以一定程度的怀疑态度对待来自该人的其他建议.

That's incorrect, and suggests you should treat other advice from that person with a degree of skepticism.

只有一个返回语句"(或更一般地说，只有一个退出点)的口头禅在您必须自己管理所有资源的语言中很重要 - 这样您就可以确保将所有清理代码放在一个地方.

The mantra of "only have one return statement" (or more generally, only one exit point) is important in languages where you have to manage all resources yourself - that way you can make sure you put all your cleanup code in one place.

它在 Java 中的用处要小得多:只要您知道应该返回(以及返回值应该是什么)，就返回.这样，阅读起来更简单——您不必采用该方法的任何其余部分来计算将要发生的其他事情(除了 finally 块).

It's much less useful in Java: as soon as you know that you should return (and what the return value should be), just return. That way it's simpler to read - you don't have to take in any of the rest of the method to work out what else is going to happen (other than finally blocks).

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