为什么它是非法/不道德的重置一个参考？ [英] Why is it illegal/immoral to reseat a reference?

问题描述

可能重复：

为什么引用在C ++中不可重用

交换两个参考变量（实践中，我可以交换实际变量）。我试图这样做通过使一个临时变量，使其中一个参考相等，但这被编译器击倒。下面是一个例子：

I am trying to more or less swap two reference variables (as practice, I could have swapped the actual variables). I tried doing this by making a temporary variable and making one of the references equal the other, but this got shot down by the compiler. Here is an example:

void Foo()
{
   //code
   int& ref1 = a;
   int& ref2 = b;
   int temp;

   temp = ref1;
   ref1 = ref2;
   ref2 = temp;

   //or, better yet
   std::swap(ref1, ref2);
}

我看到一个错误，它详细说明，他们不能重新安排，但不解释为什么。为什么？

I got an error, and looked on the faq lite. It details that they cannot be reseated, but does not explain why. Why?

这里

推荐答案

因为有没有语法来做：

int x = 0;
int y = 1;
int & r = x;

现在如果我说：

r = y;

我将y的值赋给x。如果我想重置，我需要一些特殊的语法：

I assign the value of y to x. If I wanted to reseat I would need some special syntax:

r @= y;    // maybe?

由于使用引用的主要原因是作为函数的参数和返回类型，问题，C ++的设计者似乎并不认为这是一条值得走下去的路。

As the main reason for using references is as parameters and return types of functions, where this is not an issue, it didn't seem to C++'s designers that this was a path worth going down.

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