逗号运算符如何工作 [英] How does the Comma Operator work

问题描述

逗号运算符在 C++ 中是如何工作的?

How does the comma operator work in C++?

例如，如果我这样做:

a = b, c;  

a 最终等于 b 还是 c?

Does a end up equaling b or c?

(是的，我知道这很容易测试 - 只是在这里记录，以便有人快速找到答案.)

(Yes, I know this is easy to test - just documenting on here for someone to find the answer quickly.)

更新:这个问题暴露了使用逗号运算符时的细微差别.只是为了记录这个:

Update: This question has exposed a nuance when using the comma operator. Just to document this:

a = b, c;    // a is set to the value of b!

a = (b, c);  // a is set to the value of c!

这个问题实际上是受到代码错别字的启发.本来是什么

This question was actually inspired by a typo in code. What was intended to be

a = b;
c = d;

变成了

a = b,    //  <-  Note comma typo!
c = d;

推荐答案

就等于 b.

逗号运算符的优先级低于赋值.

The comma operator has a lower precedence than assignment.

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