什么是“-"C/C ++中的运算符?

问题描述

阅读 C ++/STL的隐藏功能和死角在 comp.lang.c ++.moderated 上，我完全惊讶以下代码段在Visual Studio 2008和G ++ 4.4中均已编译并正常工作.

After reading Hidden Features and Dark Corners of C++/STL on comp.lang.c++.moderated, I was completely surprised that the following snippet compiled and worked in both Visual Studio 2008 and G++ 4.4.

代码如下:

#include <stdio.h>
int main()
{
    int x = 10;
    while (x --> 0) // x goes to 0
    {
        printf("%d ", x);
    }
}

输出:

9 8 7 6 5 4 3 2 1 0

我认为这是C，因为它也可以在GCC中使用.该标准在哪里定义，它是从哪里来的?

I'd assume this is C, since it works in GCC as well. Where is this defined in the standard, and where has it come from?

推荐答案

-> 不是运算符.实际上，它是两个单独的运算符，分别是-和> .

--> is not an operator. It is in fact two separate operators, -- and >.

条件代码的代码递减 x ，同时返回 x 的原始(未递减)值，然后将原始值与 0 进行比较使用> 运算符.

The conditional's code decrements x, while returning x's original (not decremented) value, and then compares the original value with 0 using the > operator.

为更好地理解，该语句可以写为:

while( (x--) > 0 )

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