Lecture Notes: Inserting a Node at the End of a Single Linked List

Overview

• Objective: Learn how to insert a node at the end of a singly linked list.
• Initial Setup: Assume an existing linked list with a head pointer pointing to the first node.

Key Concepts

Node Insertion Process

• Node and Address: Assume the new node to be inserted has an address 4000.
• Pointer Setup:
  • temp pointer contains the address 4000.
  • ptr pointer is used to traverse the list starting from the head.

Traversing the List

• Traverse the list using ptr until the end (last node) is reached.
• Update the link part of the end node with the new node's address using the line ptr->link = temp:
  • This makes the new node the end node.

Program Structure

• Main Function: Focuses on calling addAtEnd function to add a node at the end.
• Function Parameters:
  • head: Pointer to the first node.
  • data: Data part of the new node.

Function Explanation: addAtEnd

Function Components

• Parameters: struct node *head, int data
• Pointers Used:
  • ptr: To traverse and reach the end of the list.
  • temp: To store the new node's address.

Steps in addAtEnd Function

1. Assign Head to ptr: Initial traversal setup.
2. Create New Node:
   • Allocate memory.
   • Assign data to the new node (data = 67).
   • Initialize link part to NULL.
3. Traverse List:
   • Use while (ptr->link != NULL) to reach the last node.
   • Update ptr to point to the next node (ptr = ptr->link).
4. Insert Node:
   • After exiting loop, update last node's link with new node's address (ptr->link = temp).

Important Concepts

• Traversal Condition: Use ptr->link != NULL instead of ptr != NULL to stop at the last node, allowing for link update without setting it to NULL.

Conclusion

• The function effectively adds a new node at the end of a singly linked list.
• Assumes existence of a head pointer to a linked list.
• After execution, the node is added successfully at the end.

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