Compilare: main.cpp: In function 'std::pair<int, int> operator+(const std::pair<int, int>&, const std::pair<int, int>&)': main.cpp:20:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ main.cpp: In function 'std::pair<int, int> operator+(const std::pair<int, int>&, int)': main.cpp:27:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ main.cpp: In function 'std::pair<int, int> operator-(const std::pair<int, int>&, const std::pair<int, int>&)': main.cpp:34:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^