doubly linked list implementation java
class DoublyLinkedList {
//A node class for doubly linked list
class Node{
int item;
Node previous;
Node next;
public Node(int item) {
this.item = item;
}
}
//Initially, heade and tail is set to null
Node head, tail = null;
//add a node to the list
public void addNode(int item) {
//Create a new node
Node newNode = new Node(item);
//if list is empty, head and tail points to newNode
if(head == null) {
head = tail = newNode;
//head's previous will be null
head.previous = null;
//tail's next will be null
tail.next = null;
}
else {
//add newNode to the end of list. tail->next set to newNode
tail.next = newNode;
//newNode->previous set to tail
newNode.previous = tail;
//newNode becomes new tail
tail = newNode;
//tail's next point to null
tail.next = null;
}
}
//print all the nodes of doubly linked list
public void printNodes() {
//Node current will point to head
Node current = head;
if(head == null) {
System.out.println("Doubly linked list is empty");
return;
}
System.out.println("Nodes of doubly linked list: ");
while(current != null) {
//Print each node and then go to next.
System.out.print(current.item + " ");
current = current.next;
}
}
}
class Main{
public static void main(String[] args) {
//create a DoublyLinkedList object
DoublyLinkedList dl_List = new DoublyLinkedList();
//Add nodes to the list
dl_List.addNode(10);
dl_List.addNode(20);
dl_List.addNode(30);
dl_List.addNode(40);
dl_List.addNode(50);
//print the nodes of DoublyLinkedList
dl_List.printNodes();
}
} 