Introduction to Linked List Data Structure

Introduction to Linked List Data Structure

In this tutorial, you are going to learn about Introduction to Linked List Data Structure.

Linked List in Data Structure

A linked list is a linear collection of data elements, in which the elements are not stored at contiguous memory locations.

  • Linked list of items is arranged in order
  • Size of linked list changes as items are inserted or removed
  • Dynamic memory allocation is often used in linked list implementation

Advantages Over Arrays:

  • Dynamic size
  • Ease of insertion/deletion


  • Random access is not allowed.
  • Extra memory space for a pointer is required with each element of the list.
  • Not cache friendly.


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

Struct  Node { 
Typedef double item;
node* link;


  • A linked list is a sequence of items arranged one after another.
  • Each item in list is connected to the next item via a link.
  • Each item is placed together with the link to the next item, resulting in a simple component called a node.

Declaring a Class for Node:

struct Node
typedef double Item;
Item data; // data stored in node
Node *link; // pointer to next node

A struct is a special kind of class where all members are public. In this case there are two public member variables: data, link.

Whenever a program needs to refer to the item type, we can use the expression Node::Item.

Type of Linked List:

  1. Singly linked list
  2. Doubly linked list
  3. Circular linked list

Head Pointers, Tail Pointers

Usually, programs do not actually declare node variables. Instead, the list is accessed through one or more pointers to nodes.

Struct Node 
typedef double Item;
Item data;
Node *link;
Node *head_ptr;
Node *tail_ptr;

Null Pointer

  • The final node in the linked list does not point to a next node.
  • If the link does not point to a node, its value is set to NULL.
  • NULL is a special C++ constant, from the standard library facility
  • NULL pointer is often written 0 (zero).

This article on 'Introduction to Linked List Data Structure' is contributed by Ritika Nagar (BCA, Sharda University). If you like TheCode11, then do follow us on Facebook, Twitter and Instagram.

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