gistfile1.cpp

#include <iostream>

template<class T, class U>
std::ostream& operator<<(std::ostream& out, const std::pair<T,U>& p) {
  return out << p.first << "," << p.second;
}

int main() {
  std::pair<int, int> p(42, -1);
  std::cerr << p << std::endl;
}