Efficiently initialise std::set with a sequence of numbers

Question

An obvious (naive?) approach would be:

std::set s;
for (int i = 0; i < SIZE; ++i) {
    s.insert(i);
}

That\'s reasonable rea

Answer 1

The prettiest would be:

#include 
#include 

int main()
{
  const int SIZE = 100;
  std::set s(boost::counting_iterator(0), 
                  boost::counting_iterator(SIZE));

  return 0;
}

If you aim for raw efficiency, using the hinted insert version could be helpful:

const int SIZE = 100;
std::set s;
auto hint = s.begin();
for(int i = 0; i < SIZE; ++i)
  hint = s.insert(hint, i);

Being able to declaring hint along with the counter would be nice and give us a clean scope, but this requires struct hackery which I find a little obfuscating.

std::set s;
for(struct {int i; std::set::iterator hint;} 
      st = {0, s.begin()};
    st.i < SIZE; ++(st.i))
  st.hint = s.insert(st.hint, st.i);