Compilare: user.cpp: In function ‘void Add(std::map<int, int, std::less<int>, std::allocator<std::pair<const int, int> > >&, int, int)’: user.cpp:19: warning: NULL used in arithmetic user.cpp: In function ‘void Read()’: user.cpp:71: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:72: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:75: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:78: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void Print()’: user.cpp:83: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result