比较自我分配的指针 [英] Comparing pointers for self-assignment

问题描述

我试图重载一个简单的C ++类名为Set的包含动态数组的int运算符。对于=运算符，我首先要检查自我分配，所以我想比较2个指针，看看它们是否有相同的内存地址。这里是代码：

I am trying to overload the = operator on a simple C++ class called Set that contains a dynamic array of ints. For the = operator, I first want to check for self assignment, so I wanted to compare 2 pointers to make see if they have the same memory address. Here's the code:

Set& Set::operator=(const Set& setEqual)
{
//first check for self assignment
if(setEqual == this*)
    cout << "this is self assignment";
}

错误出错是表达式before'）'token

我相信我再次误解了指针，所以如果任何人都可以指向

I believe I'm having a misunderstanding of pointers again, so if anyone could point (ha!) me in the right direction, I'd appreciate it.

推荐答案

要检测自我指派，您需要

To detect self-assignment you need

if(&setEqual == this)

你不应该使用

if(setEqual == *this)

用于检测自我分配，因为后面的语句将调用对象的比较，这可能以您不期望的方式重载，可能会更慢。

for detecting self-assignment as the latter statement will invoke comparison of the objects, which might be overloaded in the way you don't expect and is likely slower as well.

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