What is the past-the-end iterator in STL C++?

Question

Any one could explain me what is the meaning of past-the-end. Why we call end() function past-the-end?

Answer 1

Literally, because it points one past the end of the array.

It is used because that element is empty, and can be iterated to, but not dereferenced.

int arry[] = {1, 2, 3, 4, /* end */ };
                         ^^^^^^^
                    std::end(arry) would point here.