NULL！= C ++中的值的含义是什么？ [英] What is the meaning of NULL != value in C++?

问题描述

可能重复：

我经历了一段C ++代码，遇到了像

I was going through a piece of C++ code and came across a code like

if (NULL != threadInfo)
{
  ...
  ...
}

我只是想知道使用表达式之间是否有任何区别

I was just wondering is there any difference between using the expression

if (threadInfo != NULL)
{
  ...
  ...
}

上面说的是什么。
读取第一个读取如果NULL不等于ThreadInfo，第二个读取如果threadInfo不等于NULL。对我来说第二个更有意义。

what is said above. While reading the first one reads " If NULL not equals to ThreadInfo" and the second one reads "If threadInfo not equals to NULL". To me the second one makes more sense.

推荐答案

不，没有区别。在 == 的情况下可能会有一些区别。事情是，如果你不小心写了 = 而不是 == ，编译器会在第一种情况下给出错误。

No, there is no difference. In case of == there might be some difference. The thing is that if you accidentally write = instead of == the compiler will give an error in the first case.

if (threadInfo = NULL) //always false. The compiler will give you a warning at best

if (NULL = threadInfo) //Compiler error

b $ b

我个人讨厌这种做法，认为编写可以用正常人类语言阅读的代码更好，而不是Yoda语言。

I personally hate that practice and think it's better to write code that can be read in a normal human language, not Yoda language.

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