Compilare: user.c: In function ‘main’: user.c:26:11: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen ("hotel.in", "r", stdin); ^ user.c:27:11: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen ("hotel.out", "w", stdout); ^ user.c:30:9: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d\n", &n, &m); ^ user.c:38:11: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &op); ^ user.c:42:13: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &left, &add); ^ user.c:49:13: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &left, &add); ^