Compilare: user.cpp: In member function ‘std::vector<std::pair<long long int, long long int> > Trapez::Get_Set_of_Slopes(std::vector<std::pair<long long int, long long int> >)’: user.cpp:19:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < P.size() - 1; ++i) ^ user.cpp:20:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = i + 1; j < P.size(); ++j) Slopes.push_back( { P[i].first - P[j].first, P[i].second - P[j].second } ); ^ user.cpp: In member function ‘long long int Trapez::Count(std::vector<std::pair<long long int, long long int> >)’: user.cpp:41:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < Slopes.size(); ++i) { ^