The Implementation The unique requirement for the SpecializedList is that we are able to traverse it either frontward or backward. Because a doubly linked list is linked in both directions, traversing the list either way is equally simple. Therefore, we use a reference-based doubly linked structure for our implementation. To begin our backward traversals, and to support the new insertEnd operation, it is clear that we need easy access to the end of a list. We have already seen how keeping the list reference pointing to the last element in a circular structure gives direct access to both the front element and the last element. So, we could use a doubly linked circular structure. However, another approach is also possible. We can maintain two list references, one for the front of the list and one for the back of the list. We use this approach in figure below. We use a doubly linked reference based approach, with instance variables to track the first list element, the last list element, the number of items on the list, and the positions for both the forward traversal and the backward traversal. Note that the info attribute of the SListNode class holds a value of the primitive byte type, as was discussed above. ***YOU MUST USE THIS STARTER CODE OR DOWNVOTED*** .

1. The Implementation
The unique requirement for the SpecializedList is that we are able to traverse it either frontward
or backward.
Because a doubly linked list is linked in both directions, traversing the list either way is equally
simple. Therefore,
we use a reference-based doubly linked structure for our implementation. To begin our backward
traversals, and to
support the new insertEnd operation, it is clear that we need easy access to the end of a list. We
have already seen
how keeping the list reference pointing to the last element in a circular structure gives direct
access to both the front
element and the last element. So, we could use a doubly linked circular structure. However,
another approach is also
possible. We can maintain two list references, one for the front of the list and one for the back of
the list. We use this
approach in figure below. We use a doubly linked reference based approach, with instance
variables to track the first
list element, the last list element, the number of items on the list, and the positions for both the
forward traversal
and the backward traversal. Note that the info attribute of the SListNode class holds a value of
the primitive byte
type, as was discussed above.
***YOU MUST USE THIS STARTER CODE OR DOWNVOTED***