Compilare: user.cpp: In function ‘void df(int)’: user.cpp:23: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:76: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:77: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:98: warning: ‘t.zi::poz’ may be used uninitialized in this function user.cpp:75: warning: ‘t.zi::op’ may be used uninitialized in this function