什麼將從std :: set.end（）完全在C++中返回？

Question

當你指的是cppreference，你會發現這一點：

Returns an iterator to the element following the last element of the container. This element acts as a placeholder; attempting to access it results in undefined behavior.

然後我運行下面的代碼：

std::set<int> s {1, 2, 3}; 
cout << *s.end() << endl; 

的出來說就是：，爲什麼呢？

Answer 1

What will be returned from std::set.end() exactly in c++?

它返回：

an iterator to the element following the last element of the container.

需要注意的是：

This element acts as a placeholder; attempting to access it results in undefined behavior.

 

The out put is: 3, why?

因爲：

attempting to access it results in undefined behavior.

所以它可以做任何事你的編譯器感覺就像在做什麼，返回3是一種什麼，你的編譯器顯然覺得這樣做。