Insert node at beginning of doubly linked list java

Java program for Insert node at beginning of doubly linked list. Here problem description and explanation.

// Java Program For
// insert new node at beginning of doubly linked list

// Define class of linked list Node
class LinkNode
{
    public int data;
    public LinkNode next;
    public LinkNode prev;
    public LinkNode(int data)
    {
        this.data = data;
        this.next = null;
        this.prev = null;
    }
}
public class DoublyLinkedList
{
    public LinkNode head;

    public DoublyLinkedList()
    {
        // Set inital value
        this.head = null;
    }
    // Insert new node at beginning position
    public void insert(int value)
    {
        // Create a node
        LinkNode node = new LinkNode(value);
        node.next = this.head;
        // When linked list is not empty
        if (this.head != null)
        {
            this.head.prev = node;
        }
        // Make new head
        this.head = node;
    }
    // Display node element of doubly linked list
    public void display()
    {
        if (this.head == null)
        {
            System.out.println("Empty Linked List");
        }
        else
        {
            System.out.println("  Doubly Linked List Element :");
            // Get first node of linked list
            LinkNode temp = this.head;
            // iterate linked list 
            while (temp != null)
            {
                // Display node value
                System.out.print("  " + temp.data);
                // Visit to next node
                temp = temp.next;
            }
        }
    }
    public static void main(String[] args)
    {
        DoublyLinkedList dll = new DoublyLinkedList();
        // Insert following linked list nodes
        dll.insert(70);
        dll.insert(60);
        dll.insert(50);
        dll.insert(40);
        dll.insert(30);
        dll.insert(20);
        dll.insert(10);
        //  NULL <- 10 <--> 20 <--> 30 <--> 40 <--> 50 <--> 60 <--> 70 -> NULL
        dll.display();
    }
}
Insert node in front of doubly linked list node

Output

  Doubly Linked List Element :
  10  20  30  40  50  60  70


Please share your knowledge to improve code and content standard. Also submit your doubts, and test case. We improve by your feedback. We will try to resolve your query as soon as possible.

New Comment







© 2021, kalkicode.com, All rights reserved