Compilare: main.cpp: In member function 'bool convex_hull::search(point_t, point_t)': main.cpp:33:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (mid + 1 < points.size () && area (a, b, points[mid + 1]) < 0) ~~~~~~~~^~~~~~~~~~~~~~~~ main.cpp:28:54: warning: variable 'best' set but not used [-Wunused-but-set-variable] int lb = 0, rb = ((int) points.size ()) - 1, best = 0; ^~~~ main.cpp: In function 'int main()': main.cpp:97:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("tri3.in", "r", stdin); ^ main.cpp:98:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("tri3.out", "w", stdout); ^