Compilare: user.cpp: In function ‘void add_segments_and_points(Poly)’: user.cpp:190:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i + 2 < act.size(); i++) ^ user.cpp: In function ‘Poly read_poly()’: user.cpp:149:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp: In member function ‘void Point::read()’: user.cpp:33:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf", &x, &y); ^ user.cpp: In function ‘int main()’: user.cpp:249:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("robot.in","r",stdin); ^ user.cpp:250:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("robot.out","w",stdout); ^ user.cpp:262:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^