Compilare: user.c: In function ‘main’: user.c:38:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("combinari.in","r", stdin); ^ user.c:39:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("combinari.out","w", stdout); ^ user.c:41:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &k); ^