hooluupog

    func grow(s []int) { // s is deep copied.
        s = append(s, 4, 5, 6)  // changing 's' does not effect original slice.
    }

    func grow(s *[]int) { // s is referenced.
        *s = append(*s, 4, 5, 6)  // changing 's' will always effect origin slice.
    }