在C ++中用for（; condition;）替换while（condition）的任何原因？ [英] Any reason to replace while(condition) with for(;condition;) in C++?

问题描述

看起来像

while( condition ) {
    //do stuff
}

完全等同于

for( ; condition; ) {
    //do stuff
}

是否有理由使用后者而不是前者？

Is there any reason to use the latter instead of the former?

推荐答案

没有好理由，据我所知。

There's no good reason as far as I know. You're intentionally misleading people by using a for-loop that doesn't increment anything.

更新：

根据OP对该问题的评论，我可以推测你如何在实际代码中看到这样的结构。我已经看过（和使用）这之前：

Based on the OP's comment to the question, I can speculate on how you might see such a construct in real code. I've seen (and used) this before:

lots::of::namespaces::container::iterator iter = foo.begin();
for (; iter != foo.end(); ++iter)
{
    // do stuff
}

但是这是我离开一个for循环。也许你的项目有一个循环，看起来像一次。如果你添加在循环中删除容器元素的代码，你可能必须仔细控制 iter 是否递增。这可能会导致代码看起来像这样：

But that's as far as I'll go with leaving things out of a for-loop. Perhaps your project had a loop that looked like that at one time. If you add code that removes elements of a container in the middle of the loop, you likely have to control carefully how iter is incremented. That could lead to code that looks like this:

for (; iter != foo.end(); )
{
    // do stuff

    if (condition)
    {
        iter = foo.erase(iter);
    }
    else
    {
        ++iter;
    }
}

但是，这不是没有借口，需要将其更改为while循环。

However, that's no excuse for not taking the five seconds needed to change it into a while-loop.

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