Compilare: user.cpp: In function ‘void WriteOutput()’: user.cpp:52:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(cursor_up + 1 < points_up.size() && CCW(points_down[cursor_down], points_up[cursor_up], points_up[cursor_up + 1]) < 0) { ^ user.cpp: In function ‘void ReadInput()’: user.cpp:20:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:22:53: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int x, y1, y2; scanf("%d%d%d", &x, &y1, &y2); ^