Compilare: user.cpp: In function ‘int df(int)’: user.cpp:55: warning: comparison between signed and unsigned integer expressions user.cpp:67: warning: no return statement in function returning non-void user.cpp: In function ‘int main()’: user.cpp:112: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:113: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:114: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:117: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:127: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result