Compilare: user.cpp: In function ‘void read()’: user.cpp:11: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:14: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void population(int, int)’: user.cpp:29: warning: operation on ‘m’ may be undefined user.cpp:31: warning: operation on ‘m’ may be undefined user.cpp: In function ‘int main()’: user.cpp:141: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:142: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result