c++ - How to check whether the iterator hit the end without container?

Question

For example, how to implement the following function without any other information?

bool isEnd(set<int> :: iterator itr);

I know I can do it like this, but how to do it without input variable "s"?

bool isEnd(const set<int> &s, set<int> :: iterator itr) {
    return itr == s.end();
}

Answer 1

You do not.

A range is two iterators, and you should almost always be working on a range when you are moving iterators around.

Containers are also ranges, so you can carry the container around instead, but usually you do not need the full container.