Compilare: user.cpp: In member function ‘int hash_map::hash_function(int)’: user.cpp:19: warning: no return statement in function returning non-void user.cpp: In function ‘int main()’: user.cpp:81: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:82: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:86: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:94: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result