# Insertion of linked list

There are following position are possible to insert newly created node of linked list.

1) Beginning of linked list (head position)

2) End position

3) In between linked list node

Before read this article please, viewing an animations of insertion process.

** Linked list Inserted node is: **

496, 437, 496, 501, 479, 450, 465, 451, 569, 586

** Case 1 : Insertion at start position. **

Following process to insert linked list element on start position.

Insert first element 498 in linked list. In this case linked list are empty so create a memory block using malloc function and assign data value is 498 and assign next pointer value is to Root Pointer. And assign this newly memory block to root pointer.

Step 1: Create memory block on heap area.

/* create new memory block using malloc function.*/

struct Node*new_node=(struct Node*)malloc(sizeof(struct Node));

Step 2: Assign data and pointer value.

/*Assign data and next pointer value to newly created node.*/

new_node->data=value;

new_node->next=root;

Step 3: Assign root pointer .

/*Assign root pointer to newly linked list node. */

root=new_node.

** Conclusion :** Continuous follow this three step to insert linked list node at start position

**Visualization :** Try it YourselfView Steps

Another example suppose there are following data are.

** 144, 325, 343, 44, 23, 36, 66, 612**

insert on linked list. then visualize linked list

Make This Linked List.

** Code imagination :** View to below

Below in C implementation of insert newly created node at starting position.

Case 1: Empty Linked list Output Empty linked List case 2: When linked list are not empty Output Linked list data is : 612 66 36 23 44 343 325 144 case 3: Free Of linked list Node Free linked list Node element

## Another case insert data at end of linked list.

Iterative approach in below code. To find last node of linked list its time taken by O(n). So time complexity of this program will be O(n) . Note that if already find last node then complexity will be a constant (using queue data structure).

Suppose following data are ** 144, 325, 343, 44, 23, 36, 66, 612** insert on linked list.

Following process to insert linked list element on end position.

Insert first element 144 in linked list. In this case linked list are empty so create a memory block using malloc function and assign data value is 144 and assign next pointer value is to Root Pointer. And assign this newly memory block to root pointer.

Step 1: Create memory block on heap area.

/* create new memory block using malloc function.*/

struct Node*new_node=(struct Node*)malloc(sizeof(struct Node));

Step 2: Assign data and pointer value.

/*Assign data and next pointer value to newly created node.*/

new_node->data=value;

new_node->next=NULL;

Step 3: Find last linked list node and attach newly created node.

/*linked list first node address assign on temp pointer*/

temp=root;

/*This will loop find last node of exist linked list*/

while(temp->next){

/*move temp pointer on next memory block*/

temp=temp->next;
}

/*assign this newly created node on end of list*/

temp->next=new_node;

root=new_node.

** Conclusion :** Continuous follow this steps to insert linked list node at End position

Case 1: Empty Linked list Output Empty linked List case 2: When linked list are not empty Output Linked list data is : 44 35 34 75 23 36 66 62 Free linked list Node element

### Insertion using queue data structure

When we are use queue data structure to implement linked list then there Time Complexity will be change.
Insertion time complexity : O(1).
And Deletion time complexity : O(n) to Finding delete node position.
More information visit Queue implementation of linked list .

### Insertion of between linked list node

The following post are related to insertion between linked list nodes.

* * Singly linked list insert data in ascending order

* * Singly linked list insert data in descending order

* * Single linked list insert node at middle position

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