Element at index in a std::set?

Question

I\'ve stumbled upon this problem: I can\'t seem to select the item at the index\' position in a normal std::set. Is this a bug in STD?

Below a simple ex

Answer 1

It doesn't cause a crash, it just doesn't compile. set doesn't have access by index.

You can get the nth element like this:

std::set::iterator it = my_set.begin();
std::advance(it, n);
int x = *it;

Assuming my_set.size() > n, of course. You should be aware that this operation takes time approximately proportional to n. In C++11 there's a nicer way of writing it:

int x = *std::next(my_set.begin(), n);

Again, you have to know that n is in bounds first.