// class to contain a pair of arbitrary objects

#include <iostream>
using namespace std;

class PairInt {
  public:
    PairInt(int a, int b): a_(a), b_(b) {};
    int a() const { return a_; }
    int b() const { return b_; }

  private:
    int a_;
    int b_;
};

template <typename T> class PairSame {
  public:
    PairSame(T a, T b): a_(a), b_(b) {}
    T a() const { return a_; }
    T b() const { return b_; }
  private:
    T a_;
    T b_;

};

template <typename T>
ostream& operator<<(ostream& out, const PairSame<T>& p) {
  return ( out << "(" << p.a() << "," << p.b() << ")" );
}

template <typename T1, typename T2> class Pair {
  public:
    Pair(T1 a, T2 b): a_(a), b_(b) {}
    T1 a() const { return a_; }
    T2 b() const { return b_; }
  private:
    T1 a_;
    T2 b_;

};

template <typename T1, typename T2>
ostream& operator<<(ostream& out, const Pair<T1, T2>& p) {
  return ( out << "(" << p.a() << "," << p.b() << ")" );
}

int main() {
  PairInt coppia(1,2);
  cout << "Coppia " << coppia.a() << "," << coppia.b() << endl;

  PairSame<int> c1(1,2);
  PairSame<float> c2(1.1,2.1);
  PairSame<string> c3("hello","world");
  cout << "c1 " << c1 << endl;
  cout << "c2 " << c2 << endl;
  cout << "c3 " << c3 << endl;

  Pair<int, string> c4(4,"world");
  Pair<string, Pair<int,int> > c5("world",Pair<int, int>(1,2));
  cout << "c4 " << c4 << endl;
  cout << "c5 " << c5 << endl;


  return 0;
}