Doubly linked list java: How to create and display it with code examples

If you are a developer or a programmer, Java is something that can’t be lacking for you to develop your career. Mentioning Java, one of the most important things that we can’t ignore is Java doubly linked list. In case you have no knowledge of it, this blog is for you. This is because, in this blog, ArrowHiTech will provide you most beneficial information about Doublylinkedlist.java with specific code examples for you to easily understand. So, let’s explore it right now! 

What is Java doubly linked list? 

In fact, the Doubly Linked list java is a type of linked list. The linked list is a type of linear data structure that is defined as a collection of nodes. Besides, pointers are used to connect nodes. Furthermore, there are two fields in each node: data and a pointer to the next field. The head of the Java doubly linked list is the first node, and the tail of the list is the last node.

Java
Java

What’s more, one of the singly linked list’s constraints is that it can only be visited in one direction: forward. Specifically, by giving an additional reference that points to the preceding node, the doubly linked list has addressed this constraint. The java doubly linked list list can be traversed in the backward manner using the prior pointer, making insertion and deletion operations easier. As a result, a typical node in a doubly linked list has three fields. Then, let’s take a look at these fields below:

# Data: the value of data in the node is represented by data

# Previous: represents a pointer that points to the previous node

# Next: represents a pointer that points to the next node in the list.

Doubly linked list java
Doubly Linked list java

Through this picture above, you can see the Java doubly linked list is one in which each node has two pointers pointing to the previous and next node, respectively. The head of the list is represented by node 1. The head node’s previous pointer will always point to NULL. Node one’s next pointer will point to node 2. Node 5 represents the list’s tail, with the previous pointer pointing to node 4 and the next pointer pointing to NULL.

Also read: Singly linked list java: Implementation with code examples

What is the algorithm of Doublylinkedlist.java? 

# To begin, create a Node class that represents a list node. Following that, it will consist of three properties. Specifically, they are: data, previous (pointing to the previous node), and next (pointing to the next node).

# The next step is defining a new class that will create a Java doubly linked list with two nodes: head and tail. Then, the head and tail will initially point to null.

# Moreover, the function addNode() adds a node to the list:

It initially checks to see if the head is empty.

  • First and foremost, it checks to see if the head is null before inserting the node as the head.
  • A newly added node will be pointed to by both the head and tail.
  • The previous pointer of the head will point to null, and the next pointer of the tail will point to null.
  • After that, the new node will be added to the end of the list if the head is not null, with the previous pointer of the new node pointing to the tail.
  • The new node will take on the role of the new tail. Also, the next pointer in Tail’s chain will be null.

# display() will let you know all of the nodes in the list

  • Create a new node called ‘current’ that points to the head.
  • Print current.data until it reaches null.
  • In each iteration, current will point to the next node in the list.
how to create Doubly linked list java
Everything about doublylinkedlist.java

What does Java doubly linked list a implement? 

Now, let’s have a glance at the following program to understand its implementation in detail:

public class DoublyLinkedList {    

    //Represent a node of the doubly linked list  

    class Node{  

        int data;  

        Node previous;  

        Node next;  

        public Node(int data) {  

            this.data = data;  

        }  

    }  

    //Represent the head and tail of the doubly linked list  

    Node head, tail = null;  

    //addNode() will add a node to the list  

    public void addNode(int data) {  

        //Create a new node  

        Node newNode = new Node(data);  

        //If list is empty  

        if(head == null) {  

            //Both head and tail will point to newNode  

            head = tail = newNode;  

            //head’s previous will point to null  

            head.previous = null;  

            //tail’s next will point to null, as it is the last node of the list  

            tail.next = null;  

        }  

        else {  

            //newNode will be added after tail such that tail’s next will point to newNode  

            tail.next = newNode;  

            //newNode’s previous will point to tail  

            newNode.previous = tail;  

            //newNode will become new tail  

            tail = newNode;  

            //As it is last node, tail’s next will point to null  

            tail.next = null;  

        }  

    }  

    //display() will print out the nodes of the list  

    public void display() {  

        //Node current will point to head  

        Node current = head;  

        if(head == null) {  

            System.out.println(“List is empty”);  

            return;  

        }  

        System.out.println(“Nodes of doubly linked list: “);  

        while(current != null) {  

            //Prints each node by incrementing the pointer.  

            System.out.print(current.data + ” “);  

            current = current.next;  

        }  

    }  

    public static void main(String[] args) {  

        DoublyLinkedList dList = new DoublyLinkedList();  

        //Add nodes to the list  

        dList.addNode(1);  

        dList.addNode(2);  

        dList.addNode(3);  

        dList.addNode(4);  

        dList.addNode(5);  

        //Displays the nodes present in the list  

        dList.display();  

    }  

}  

Then, you will achieve the output below:

code example
Output

What does Circular Java doubly linked list mean?

Now, coming to the Circular Doubly linked list Java – one of the most complicated structures in Java. For more detail, the address of the first node is contained in the last node of the doubly linked list, and the address of the last node is contained in the first node. There is a cycle in a circular doubly linked list, and none of the node pointers are null.

Then, you should explore the following diagram to dig down further information about Circular Java doubly linked list:

Circular Doubly Linked list java
Circular java doubly linked list

As you probably see through this diagram above, the last node’s next pointer points to the first node. Also, the first node’s previous pointer points to the last node.

In reality, Circular Java doubly linked list is widely used in the software business. In addition to the software’s area, this is also integrated in a musical app with a playlist. Simply speaking, when you finish playing all of the songs in the playlist, the playlist automatically returns to the first song at the end of the last song. Circular lists are used to do this.

In conclusion

In short, in this article, ArrowHiTech delivered you all about Java doubly linked list and as well as instructed you to work well with Java thanks to several code examples. Above all, if you have any inquiries about this topic, let’s CONTACT US. At ArrowHiTech, our professionals have expertise in building business-specific Web applications/ Mobile App that meet your high expectations and quality standards

Tags

Share