Compilare: user.cpp: In function ‘void df(int)’: user.cpp:26: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void df2(int)’: user.cpp:105: warning: comparison between signed and unsigned integer expressions user.cpp:118: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:126: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:127: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:129: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:132: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:145: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result