Compilare: user.cpp: In function ‘int main()’: user.cpp:245: warning: unused variable ‘_NN’ user.cpp:222: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:223: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:227: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:231: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result