A linked list is a linear data structure where elements are not stored at contiguous location. Instead the elements are linked using pointers.

In a linked list data is stored in nodes and each node is linked to the next and, optionally, to the previous. Each node in a list consists of the following parts: 1) data 2) A pointer (Or reference) to the next node 3) Optionally, a pointer to the previous node

The first node in a linked list is referred to as the head node. In the given example, P-i is the head node.

Like arrays, a linked list is a linear data structure. Data in a linked list is stored in the form of nodes. Each node in a list consists of the following parts: 1) data 2) A pointer (Or reference) to the next node 3) An optional pointer to the previous node

A linked list is represented by a pointer to the first node of the linked list. The first node is called head. If the linked list is empty, then the value of head is NULL.

A linked list exposes the ability to traverse the list from one node to another node. The starting node is considered the head node from where the list can be traversed.

When removing a node from the middle of a linked list, it is necessary to adjust the link on the previous node so that it points to the following node. In the given illustration, the node a1 must point to the node a3 if the node a2 is removed from the linked list.

When adding a new node to the start of a linked list, it is necessary to maintain the list by giving the new head node a link to the current head node. For instance, to add a new node a0 to the begining of the linked list, a0 should point to a1.