Compilare: user.c: In function ‘main’: user.c:6:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("modulo.in", "r", stdin); ^ user.c:7:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("modulo.out", "w", stdout); ^ user.c:8:7: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld%lld", &a, &b, &c); ^