Compilare: user.cpp: In function ‘PTX intersection(const PTX&, const PTX&, const PTX&, const PTX&)’: user.cpp:77:25: warning: unused variable ‘x’ [-Wunused-variable] f64 an, am, bn, bm, x, y; ^ user.cpp:77:28: warning: unused variable ‘y’ [-Wunused-variable] f64 an, am, bn, bm, x, y; ^ user.cpp: In function ‘std::vector<PTX> make_hull(std::vector<PTX>)’: user.cpp:110:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<ptr.size(); ++i) { ^ user.cpp:118:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<ue.size(); ++i) ^ user.cpp: In function ‘int sgn(f64)’: user.cpp:49:1: warning: control reaches end of non-void function [-Wreturn-type] } ^