用cout语句执行while循环 [英] Do while loop with a cout statement

问题描述

所以我对 do / while 循环有一个一般性的问题。我正在学习C ++，我知道您可以编写类似的内容：

So I have a general question about the do/while loop. I'm learning C++ and I know that you can write something like that:

do{
....
} while(a<10 && cout<<"message");

重点是，我知道这在c ++中是可能的，但是我们真的做到了吗？我的意思是， cout 东西在内部一段时间了吗？

The point is, that i know this is possible in c++, but do we really do that? I mean, the "cout" thing inside the while?

推荐答案

事实是有人这样做（即，将函数作为条件评估的一部分）。这在Shell脚本中很有意义，但是如果您不使用Shell脚本，则有时不清楚某些函数的返回值是什么。我无法告诉您cout<<<<<>"消息"会立即返回，但是我确实知道，如果将其写入循环主体中，它将满足我的要求，并且如果我将它丢弃返回值

The fact is some people do this (i.e. run a function as part of the condition evaluation). It makes sense in a shell script, but if you're not using a shell script, it's sometimes not clear what the return value is for some functions. I couldn't tell you what cout<<"message" returns offhand, but I do know that if you write it inside the loop body, it would do what I want, and it would 'throw away' the return value if I don't use it.

要编写更清晰的代码（包括您的未来自我），其他人可以理解，我只会评估明显返回true / false的条件，而不是 0 / not-0或 0/1（在不同语言中可能有所不同）。

To write cleaner code that others including your future-self can understand, I would only evaluate conditions which obviously return true/false as opposed to "0/not-0", or "0/1" which may different in different languages.

最重要的是，让编译器为您提高效率，并且代码给其他人，而不是编译器。

Bottom line is, let the compiler make things more efficient for you, and code for other people, not for the compiler.

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