Compilare: user.cpp: In function ‘int main()’: user.cpp:92:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 2; i < v.size(); i++) { ^ user.cpp:99:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < hull.size(); i++) { ^ user.cpp:110:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 1; j < hull.size(); j++) { ^ user.cpp:59:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rubarba.in", "r", stdin); ^ user.cpp:60:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rubarba.out", "w", stdout); ^ user.cpp:61:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:71:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^