Compilare: user.cpp: In function ‘std::pair<int, int> read_dot()’: user.cpp:53: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘int main(int, char* const*)’: user.cpp:135: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:136: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:138: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result