Compilare: user.cpp: In function ‘int main()’: user.cpp:68:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(hull.size()>t && ccw(pts[hull[hull.size()-2]], pts[hull[hull.size()-1]], pts[i])>0) { ^ user.cpp:79:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1; i<hull.size()-1; ++i) ^ user.cpp:95:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=3; i<hull.size()-1; ++i) { ^ user.cpp:109:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=4; i<hull.size(); ++i) { ^ user.cpp:39:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mosia.in", "r", stdin); ^ user.cpp:40:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mosia.out", "w", stdout); ^ user.cpp:46:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:48:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y,&p); ^