Compilare: user.cpp: In function ‘std::istream& operator>>(std::istream&, const Point&)’: user.cpp:22:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘std::ostream& operator<<(std::ostream&, const Point&)’: user.cpp:25:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘Polygon convexHull(Polygon&)’: user.cpp:35:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ( i == poly.size() ) inc = -1; ^