C Program for Insertion at the End of the Singly Linked List

March 20, 2025

Insertion in singly linked list at the end

Below we are going to look at the C Program for Insertion at the End of the Singly Linked List. Follow the detailed steps and code below to do the same 0

Insertion at the end of the singly linked list using C

Implementation:-

  • Create a new node, assign its data value
  • Since this new node will be the last node its next will be NULL
  • Traverse to the current last node of the linked list
  • Set the current last node’s next to this new node

If the linked list was initially empty and we were entering the first node, change the head from NULL to this new Node.

Insertion at end in Singly Linked List

Deletion in singly Linked List

Reverse a linked list without changing links between nodes

Reverse a linked list by changing links between nodes

Linked List insertion in the middle

Print reverse of a linked list without actually reversing

Declare Head & mark it NULL

struct Node{
    int data;
    struct Node *next;
};

struct Node* head = NULL;
LL end 1

Create a Node

void insertEnd(struct Node** head, int data){
    
    // since this will be the last node so it will point to NULL
    struct Node* newNode = (struct Node*) malloc(sizeof(struct Node));
    newNode->data = data;
    newNode->next = NULL;
}
LL insertion end 2

If its the first node being entered

void insertEnd(struct Node** head, int data){
    
    // since this will be the last node so it will point to NULL
    struct Node* newNode = (struct Node*) malloc(sizeof(struct Node));
    newNode->data = data;
    newNode->next = NULL;

    // if Linked List is empty its is first node being entered 
    if(*head == NULL){ 
        *head = newNode; 
        return; 
    }
}
LL end 3

Otherwise Traverse to the current last node

void insertEnd(struct Node** head, int data){
    
    // since this will be the last node so it will point to NULL
    struct Node* newNode = (struct Node*) malloc(sizeof(struct Node));
    newNode->data = data;
    newNode->next = NULL;

    // if Linked List is empty its is first node being entered
    if(*head == NULL){
        *head = newNode;
        return;
    }


    // otherwise find the current last node
    
    // create another variable to traverse the LL
    // *head should not be used as we do not want to change head
    struct Node* temp = *head;
    
    // traverse to the last node of Linked List
    while(temp->next!=NULL)
        temp = temp->next;
    
    // assign last node's next to this newNode
    temp->next = newNode;


}

Full Program for Insertion at the End of the Singly Linked List:-

Let us look at the full program for it below –
Run 
#include<stdio.h>
#include<stdlib.h>

struct Node
{
  int data;
  struct Node *next;
};

void insertEnd (struct Node **head, int data)
{

  // since this will be the last node so it will point to NULL
  struct Node *newNode = (struct Node *) malloc (sizeof (struct Node));
  newNode->data = data;
  newNode->next = NULL;

  // if Linked List is empty its is first node being entered
  if (*head == NULL)
    {
      *head = newNode;
      return;
    }
  // otherwise find the current last node

  // create another variable to traverse the LL
  // *head should not be used as we do not want to change head
  struct Node *temp = *head;

  // traverse to the last node of Linked List
  while (temp->next != NULL)
    temp = temp->next;

  // assign last node's next to this newNode
  temp->next = newNode;

  printf ("%d inserted at the end\n", data);
}


void display (struct Node *node)
{

  // as linked list will end when Node is Null
  while (node != NULL)
    {
      printf ("%d ", node->data);
      node = node->next;
    }
  printf ("\n");
}

int
main ()
{
  //creating 4 pointers of type struct Node
  //So these can point to address of struct type variable
  struct Node *head = NULL;
  struct Node *node2 = NULL;
  struct Node *node3 = NULL;
  struct Node *node4 = NULL;

  // allocate 3 nodes in the heap 
  head = (struct Node *) malloc (sizeof (struct Node));
  node2 = (struct Node *) malloc (sizeof (struct Node));
  node3 = (struct Node *) malloc (sizeof (struct Node));
  node4 = (struct Node *) malloc (sizeof (struct Node));

  head->data = 22;		// data set for head node 
  head->next = node2;		// next pointer assigned to address of node2 

  node2->data = 30;
  node2->next = node3;

  node3->data = 24;
  node3->next = node4;

  node4->data = 20;
  node4->next = NULL;

  /*No need for & i.e. address as we do not
     need to change head address
   */
  printf ("Linked List Before Operations : ");
  display (head);

  insertEnd (&head, 5);
  insertEnd (&head, 6);
  insertEnd (&head, 7);
  insertEnd (&head, 8);

  printf ("Linked List After Operations : ");
  display (head);

  return 0;
}

Output

Linked List Before Operations: 22 30 24 20 
5 inserted at the end
6 inserted at the end
7 inserted at the end
8 inserted at the end
Linked List After Operations : 22 30 24 20 5 6 7 8