Compilare: user.cpp: In function ‘long double arie(std::vector<std::pair<long double, long double> >)’: user.cpp:25:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<V.size();i++){V[i].first-=V[0].first;V[i].second-=V[0].second;} ^ user.cpp:29:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<V.size();i++) ^