Compilare: user.cpp: In constructor ‘convexhull::convexhull(std::vector<std::pair<double, double> >)’: user.cpp:29:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=3;i<v.size();i++) insert(v[i]); ^ user.cpp: In function ‘int main()’: user.cpp:87:39: 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); ^ user.cpp:88:41: 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); ^ user.cpp:92:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:95:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf",&p.x,&p.y); ^ user.cpp:102:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf",&p.x,&p.y); ^