Compilare: user.cpp: In function ‘void convex_hull()’: user.cpp:57:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2; i < V.size(); i++) { ^ user.cpp:69:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < st.size(); i++) { ^ user.cpp:76:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < st.size() - 1; i++) { ^ user.cpp:82:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < st.size() - 1; i++) { ^ user.cpp:91:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2; i < V.size(); i++) { ^ user.cpp:104:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < st.size() - 1; i++) { ^ user.cpp: In function ‘int main()’: user.cpp:176:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < conv.size(); i++) { ^ user.cpp:186:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < conv.size(); i++) { ^ user.cpp:163:37: 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); ^ user.cpp:164:39: 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); ^ user.cpp:166:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ", &N, &M); ^ user.cpp:169:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf ", &x, &y); ^ user.cpp:220:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf ", &x, &y); ^