Compilare: user.cpp: In function ‘void afis()’: user.cpp:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘int main()’: user.cpp:47: warning: operation on ‘pq1’ may be undefined user.cpp:51: warning: operation on ‘pq2’ may be undefined user.cpp:56: warning: operation on ‘pq1’ may be undefined user.cpp:59: warning: operation on ‘pq2’ may be undefined