#include <iostream>
#include <set>
#include <iterator>
using std::set;
using std::cout;
using std::endl;
void print(const set<int>& st)
{
for (auto element : st) {
cout << element << ' ';
}
cout << endl;
}
int main()
{
set<int> st;
std::insert_iterator<set<int> > itr(st, st.begin());
*itr = 1;
itr++;
*itr = 2;
itr++;
*itr = 3;
itr++;
*itr = 4;
print(st);
}
/*
run:
1 2 3 4
*/