Doubly Linked In C++ As in the singly linked list, the doubly linked list also has a head and a tail. The previous pointer of the head is set to NULL as this is the first node. The next pointer of the tail node is set to NULL as this is the last node.

What is the tail of a doubly linked list?

Just like the Singly Linked List, the first node in the Doubly Linked List is also called the head and the last node is also called the tail. In Doubly Linked List each node stores three things, data (integer or string), a reference to the next node and a previous node.

### Do doubly linked lists need a tail?

A Doubly linked list is a linked list that consists of a set of sequentially linked records called nodes. Each node contains two fields that are references to the previous and to the next node in the sequence of nodes. Also, we need to maintain two pointers, head (points to first node) and tail (points to last node).

The first and last node of a linked list usually are called the head and tail of the list, respectively. Thus, we can traverse the list starting at the head and ending at the tail. The tail node is a special node, where the next pointer is always pointing or linking to a null reference, indicating the end of the list.

• Every node of DLL Require extra space for an previous pointer(This can be overcome by implementing XOR Linked list)
• All operations require an extra pointer previous to be maintained.

Following are advantages/disadvantages of doubly linked list over singly linked list. 1) A DLL can be traversed in both forward and backward direction. 2) The delete operation in DLL is more efficient if pointer to the node to be deleted is given. 3) We can quickly insert a new node before a given node.

### Which operation is more efficient in doubly linked list?

It seems that insertion and deletion are more efficient in doubly linked list than singly linked list.

Is Tail Next always NULL?

tail. next is always NULL.