Compilare: user.cpp: In function ‘int main()’: user.cpp:40:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("melc.in", "r", stdin); ^ user.cpp:41:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("melc.out", "w", stdout); ^ user.cpp:43:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf %d", &x, &y, &n); ^ user.cpp: In member function ‘void point::read(double, double)’: user.cpp:14:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf %lf %d", &this->x, &this->y, &id); ^