public class DoublyLinkedList1 {

class Node{

int data;

Node prev;

Node next;

Node(int data){

this.data=data;

this.next=null;

this.prev=null;

}

}

Node head=null;

Node tail=null;

public void addNode(int data) {

Node n=new Node(data);

if(head==null) {

head=n;

tail=n;

}

else {

tail.next=n;

n.prev=tail;

tail=n;

}

}

void insertAtstart(int data) {

Node n=new Node(data);

if(head==null) {

head=n;

tail=n;

}

else {

n.next=head;

head.prev=n;

head=n;

}

}

void insertAtend(int data) {

Node n=new Node(data);

if(head==null) {

head=n;

tail=n;

}

else {

tail.next=n;

n.prev=tail;

tail=n;

}

}

void insertAtAnyposition(int data,int pos) {

Node n=new Node(data);

Node temp=head;

Node ptr=temp.next;

if(head==null) {

head=n;

tail=n;

}

else {

for(int i=1; i<pos-1; i++) {

temp=ptr;

ptr=ptr.next;

}

temp.next=n;

n.prev=temp;

n.next=ptr;

ptr.prev=n;

}

}

public void display() {

Node temp=head;

if(head==null) {

System.out.println("List is Empty");

return;

}

while(temp !=null) {

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

temp=temp.next;

}

System.out.println();

}

public static void main(String[] args) {

DoublyLinkedList1 d1=new DoublyLinkedList1();

d1.addNode(10);

d1.addNode(20);

d1.addNode(30);

d1.addNode(40);

d1.addNode(50);

d1.display();

System.out.println("After Inserting The Element At First Position");

d1.insertAtstart(100);

d1.display();

System.out.println("After Inserting The Elements At End Position");

d1.insertAtend(200);

d1.display();

System.out.println("After Inserting The Elements At any Position");

d1.insertAtAnyposition(500,4);

d1.display();

}

}