Compilare: main.cpp: In function 'void convex_hull()': main.cpp:61:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2; i < V.size(); i++) ~~^~~~~~~~~~ main.cpp:76:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < st.size() - 1; i++) ~~^~~~~~~~~~~~~~~ main.cpp:84:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2; i < V.size(); i++) ~~^~~~~~~~~~ main.cpp:99:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < st.size() - 1; i++) ~~^~~~~~~~~~~~~~~ main.cpp: In function 'void delete_next(std::set<std::pair<double, std::pair<double, double> > >::iterator, std::pair<double, double>)': main.cpp:126:12: warning: unused variable 'd' [-Wunused-variable] double d = det(P, (*it1).second, (*it2).second) < -eps; ^ main.cpp: In function 'int main()': main.cpp:149:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < conv.size(); i++) ~~^~~~~~~~~~~~~ main.cpp:155:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < conv.size(); i++) ~~^~~~~~~~~~~~~ main.cpp:165:28: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::set<std::pair<double, std::pair<double, double> > >::size_type {aka long unsigned int}' [-Wformat=] printf("%d\n", S.size()); ^ main.cpp:185:40: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::set<std::pair<double, std::pair<double, double> > >::size_type {aka long unsigned int}' [-Wformat=] printf("%d\n", S.size()); ^ main.cpp:191:32: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::set<std::pair<double, std::pair<double, double> > >::size_type {aka long unsigned int}' [-Wformat=] printf("%d\n", S.size()); ^ main.cpp:138:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("terenuri.in", "r", stdin); ^ main.cpp:139:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("terenuri.out", "w", stdout); ^ main.cpp:140:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ", &N, &M); ^ main.cpp:144:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf ", &x, &y); ^ main.cpp:169:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf ", &x, &y); ^