I'm doing something and I have this:

//main.cpp file

 template<typename t1, typename t2>
 std::ostream& operator<<(std::ostream& os, const std::pair<t1, t2>& pair)
 {
     return os << "< " << pair.first << " , " << pair.second << " >";
 }

int main() 
 {
  std::map<int, int> map = { { 1, 2 }, { 2, 3 } };
  std::cout << *map.begin() << std::endl;//This works
  std::copy(map.begin(), map.end(),
  std::ostream_iterator<std::pair<int,int> >(std::cout, " "));//this doesn't work


  }

I guess this is not working because in the std::copy algorithm the operator isn't defined, but what can I do?