Compilare: user.cpp: In function ‘int main()’: user.cpp:12:8: warning: variable ‘in’ set but not used [-Wunused-but-set-variable] FILE *in, *out; ^~ user.cpp:12:13: warning: variable ‘out’ set but not used [-Wunused-but-set-variable] FILE *in, *out; ^~~ user.cpp:16:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &n); ^ user.cpp:17:57: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (long long i = 1; i <= n; ++i) scanf("%lld", &v[i]); ^