Accessing std::set container by index position

You like it or not? Accessing an element of a set container by index position is different from the vector container as it doesn't support operator[]. There is a weird way of doing this. Before I got to aware this shortcut, I was doing it in this manner:

   set<int> s;
   set<int>::iterator is;
   for (is = s.begin(); is != s.end(); is++)
      ...

This will loop until my desire string is found. Unlike vector, I can not do something like this: s[0]. The compiler will never allow this shit to proceed further. Sigh! If it is not supported, then I have to find the other way. As of my finding, this seems to be workable:

   ...

   str = (*std::next(s.begin(),4)).c_str();
   ...

With this, I'll be able to access the 4th elements of s. I'm sure the 4th element is not null, otherwise that code will cause my shit to blow up during runtime.