Compilare: user.c: In function ‘main’: user.c:41:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sdo.in", "r", stdin); ^ user.c:42:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sdo.out", "w", stdout); ^ user.c:44:7: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ user.c:46:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i]); ^