Delete node in Doubly Linked List Java

PROGRAM TO DELETE A DOUBLY LINKED LIST NODE AT A GIVEN POSITION

class Node

{

    int data;

    Node next, prev;

}

 

class MAIN

{

    static Node head = null;

    // Function to delete a node

    // in a Doubly Linked List.

    // head_ref --> pointer to head node pointer.

    // del --> pointer to node to be deleted.

    static Node deleteNode(Node del)

    {

        // base case

        if (head == null || del == null)

            return null;

 

        // If node to be deleted is head node

        if (head == del)

            head = del.next;

 

        // Change next only if node to be

        // deleted is NOT the last node

        if (del.next != null)

            del.next.prev = del.prev;

 

        // Change prev only if node to be

        // deleted is NOT the first node

        if (del.prev != null)

            del.prev.next = del.next;

 

        del = null;

 

        return head;

    }

 

    // Function to delete the node at the

    // given position in the doubly linked list

    static void deleteNodeAtGivenPos(int n)

    {

        /* if list in NULL or

          invalid position is given */

        if (head == null || n <= 0)

            return;

 

        Node current = head;

        int i;

 

        /*

        * traverse up to the node at

          position 'n' from the beginning

        */

        for (i = 1; current != null && i < n; i++)

        {

            current = current.next;

        }

         

        // if 'n' is greater than the number of nodes

        // in the doubly linked list

        if (current == null)

            return;

 

        // delete the node pointed to by 'current'

        deleteNode(current);

    }

 

    // Function to insert a node

    // at the beginning of the Doubly Linked List

    static void push(int new_data)

    {

        // allocate node

        Node new_node = new Node();

 

        // put in the data

        new_node.data = new_data;

 

        // since we are adding at the beginning,

        // prev is always NULL

 

        new_node.prev = null;

 

        // link the old list off the new node

        new_node.next = head;

 

        // change prev of head node to new node

        if (head != null)

            head.prev = new_node;

 

        // move the head to point to the new node

        head = new_node;

    }

 

    // Function to print nodes in a

    // given doubly linked list

    static void printList()

    {

        Node temp = head;

        if (temp == null)

            System.out.print("Doubly Linked list empty");

 

        while (temp != null)

        {

            System.out.print(temp.data + " ");

            temp = temp.next;

        }

        System.out.println();

    }

 

    // Driver code

    public static void main(String[] args)

    {

        // Create the doubly linked list:

        // 10<->8<->4<->2<->5

 

        push(5);

        push(2);

        push(4);

        push(8);

        push(10);

 

        System.out.println("Doubly linked "

                           +"list before deletion:");

        printList();

 

        int n = 2;

         

        // delete node at the given position 'n'

        deleteNodeAtGivenPos(n);

        System.out.println("Doubly linked "

                           +"list after deletion:");

        printList();

    }

}

OUTPUT:

Doubly linked list before deletion:
10 8 4 2 5
Doubly linked list after deletion:
10 4 2 5

CREDITS: https://www.geeksforgeeks.org/delete-doubly-linked-list-node-given-position/