Compilare: user.cpp: In function ‘std::vector<std::pair<double, double> > getHull(size_t, Point)’: user.cpp:43:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(k >= t && turn(hull[k-2],hull[k-1],points[i]) == -1) k--; ^ user.cpp: In function ‘double area(std::vector<std::pair<double, double> >)’: user.cpp:53:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < poly.size()-1; ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:71:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < n; ++i) { ^ user.cpp:78:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < m; ++i) { ^