Compilare: user.c: In function ‘main’: user.c:23:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen(IN, "r", stdin); ^ user.c:24:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen(OUT, "w", stdout); ^ user.c:26:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lu %lu", &n, &p); ^