Doubly Linked List is a variation of Linked list in which navigation is
possible in both ways, either forward and backward easily as compared
to Single Linked List.
Every nodes in the doubly linked list has three fields: LeftPointer,
RightPointer and Data.
LeftPointer = Left pointer points towards the left node.
RightPointer = Right pointer points towards the right node.
Data = Node which stores the data.
The last node has a next link with value NULL, marking the end of the
list, and the first node has a previous link with the value NULL. The
start of the list is marked by the head pointer.
C Representation of Doubly Linked List
Structure of doubly link list will contain three fields LeftPointer (prev),
RightPointer (next), and the data as shown below
struct Node* next;
struct Node* prev;