Compilare: user.cpp: In function ‘void construct_hull(const punct&, const std::vector<punct>&, std::deque<punct>&)’: user.cpp:31:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < pts.size(); ++i){ ^ user.cpp: In function ‘int main()’: user.cpp:47:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); ++i){ ^ user.cpp:74:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < hull.size(); ++i){ ^