#include #include template class pair { public: T first; U second; pair(T t= T(), U u=U()):first(t),second(u) {} bool operator==(pair rhs) { if(first == rhs.first && second == rhs.second) { return true; } return false; } bool operator!=(pair rhs) { if(*this == rhs) { return false; } return true; } bool operator<(pair rhs) { if((first < rhs.first) && (second (pair rhs) { if(*this < rhs) { return false; } return true; } bool operator<=(pair rhs) { if((*this == rhs) || (*this < rhs)) { return true; } return false; } bool operator>=(pair rhs) { if((*this == rhs) || (*this > rhs)) { return true; } return false; } }; template pair make_pair(V t, W u) { return pair(t,u); } template void swap( pair& x, pair& y ) { pair temp; temp = x; x = y; y = temp; } template struct __pair_get; template<> struct __pair_get<0> { template static constexpr _Tp1& __get(pair<_Tp1, _Tp2>& __pair) noexcept { return __pair.first; } }; template<> struct __pair_get<1> { template static constexpr _Tp2& __get(pair<_Tp1, _Tp2>& __pair) noexcept { return __pair.second; } }; template constexpr auto get(pair<_Tp1, _Tp2>& __in) -> decltype ((_Int == 0) ? __in.first: __in.second) { return __pair_get<_Int>::__get(__in); } template constexpr auto get(pair<_Tp1, _Tp2>& __in) { return typeid(T) == typeid(__in.first) ? __in.first : __in.second; } int main() { pair PAIR1 = make_pair(300,'B'); pair PAIR2 = make_pair(200,'A'); std::cout << PAIR1.first << " " ; std::cout << PAIR1.second << std::endl ; std::cout << PAIR2.first << " " ; std::cout << PAIR2.second << std::endl ; swap(PAIR1,PAIR2); std::cout << PAIR1.first << " " ; std::cout << PAIR1.second << std::endl ; std::cout << PAIR2.first << " " ; std::cout << PAIR2.second << std::endl ; auto p = make_pair(100, 3.14); std::cout << '(' << get<0>(p) << ", " << get<1>(p) << ")\n"; std::cout << '(' << get(p) << ", " << get(p) << ")\n"; return 0; }

pair.cpp