Compilare: user.cpp: In function ‘int main()’: user.cpp:9:7: warning: variable ‘in’ set but not used [-Wunused-but-set-variable] FILE *in,*out; ^ user.cpp:9:11: warning: variable ‘out’ set but not used [-Wunused-but-set-variable] FILE *in,*out; ^ user.cpp:13:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^