Compilare: user.c: In function ‘update’: user.c:27:12: warning: unused variable ‘nm’ [-Wunused-variable] int m, nm; ^ user.c: In function ‘main’: user.c:58:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.c:61:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbint.in", "r", stdin); ^ user.c:62:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbint.out", "w", stdout); ^ user.c:63:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &N, &M); ^ user.c:68:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", vals + i); ^ user.c:72:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &op, &n, &v); ^