Compilare: user.cpp: In function ‘void df(int)’: user.cpp:27: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void df2(int)’: user.cpp:106: warning: comparison between signed and unsigned integer expressions user.cpp:119: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:127: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:128: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:130: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:133: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:144: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result