Eroare de compilare: user.cpp: In function ‘void convex_hull(std::vector<pt>&)’: user.cpp:28:35: error: ‘sort’ was not declared in this scope sort (a.begin(), a.end(), &cmp); ^ user.cpp: In function ‘int main()’: user.cpp:54:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("infasuratoare.in","r",stdin); ^ user.cpp:55:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("infasuratoare.out","w",stdout); ^ user.cpp:56:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^ user.cpp:58:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf",&X,&Y); ^