Compilare: user.c: In function ‘main’: user.c:45:11: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen ("inv.in", "r", stdin); ^ user.c:46:11: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen ("inv.out", "w", stdout); ^ user.c:48:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.c:52:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &v[i]); ^