Which type of linked list stores the address of the header node in the next field of the last node ? 

The correct answer is Circular linked list.

Key Points

• A circular linked list is a linked list where the last node points back to the first node instead of pointing to null.
  • In a circular linked list, the address of the header node is stored in the next field of the last node.
  • This allows for continuous traversal of the list without a defined end, looping back to the beginning after reaching the last node.
  • Circular linked lists can be singly or doubly linked, but the key characteristic is the circular structure.
  • Common operations such as insertion and deletion can be performed efficiently in a circular linked list.
  • Circular linked lists are useful in applications where the entire list needs to be accessed in a loop, such as in round-robin scheduling.

Additional Information

• In a singly linked list, each node points to the next node, and the last node points to null.
• In a doubly linked list, each node has two pointers: one to the next node and another to the previous node.
• A circular header linked list is a variant where a header node is used, and it also has a circular structure.
• Circular linked lists are particularly useful in implementing data structures such as queues and for applications that require a circular buffer.

Source Code Example

class Node {
    int data;
    Node next;
    Node(int d) {
        data = d;
        next = null;
    }
}

class CircularLinkedList {
    Node head;

    CircularLinkedList() {
        head = null;
    }

    void addToTheLast(Node node) {
        if (head == null) {
            head = node;
            head.next = head;
        } else {
            Node temp = head;
            while (temp.next != head) {
                temp = temp.next;
            }
            temp.next = node;
            node.next = head;
        }
    }

    void printList() {
        if (head == null) return;
        Node temp = head;
        do {
            System.out.print(temp.data + " ");
            temp = temp.next;
        } while (temp != head);
    }

    public static void main(String[] args) {
        CircularLinkedList list = new CircularLinkedList();
        list.addToTheLast(new Node(1));
        list.addToTheLast(new Node(2));
        list.addToTheLast(new Node(3));
        list.addToTheLast(new Node(4));

        System.out.println("Circular Linked List:");
        list.printList();
    }
}