I tried to find the index of the upper_bound of an integer in a set.

set<int> s = {1,2,3,4,5};
int ind = s.upper_bound(2) - s.begin();
cout << ind << "\n";

But it's showing error. I did similar thing with vectors previously. Code looks like the following:

vector<int> v = {1,2,3,4,5};
int ind = v.upper_bound(v.begin(), v.end(), 2) &mdash; v.begin();
cout << ind << "\n;

The above code nicely executes the desired task. Why it's not working for set and multiset and what to do if we want to do the same task with a set or multiset without traversing the whole set?

Thanks for your patience!