DoublyLinkedList-Ralph

package com.its101.prwk05_06;

public class DoublyLinkedList {

    // node of the doubly linked list
    public static class Node {
        String data;
        Node previous;
        Node next;

        public Node(String data) {
            this.data = data;
        }
    }

    // declare head node and last node
    Node head, last = null;

    // createNode() creates new node to the list
    public void createNode(String data) {
        // create new node
        Node newNode = new Node(data);

        // if list is empty
        if(head == null) {
            // both head and last will point to newNode
            head = last = newNode;
            // head node's previous will point to null
            head.previous = null;
            // last node's next will point to null, as it is the last node of the list
            last.next = null;
        } else {
            // newNode will be added after last node such that last node's next will point to newNode
            last.next = newNode;
            // newNode's previous will point to last node
            newNode.previous = last;
            // newNode will become new last node
            last = newNode;
            // it is last node, last node next will point to null
            last.next = null;
        }
    }

    // printNode() prints the nodes of the list
    public void printNode() {
        // 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;
        }
        System.out.println();
    }

    public static void main(String[] args) {

        DoublyLinkedList studentsList = new DoublyLinkedList();

        //Create new nodes to the Linked List and assign a data value
        studentsList.createNode("ralph");
        studentsList.createNode("espe");
        studentsList.createNode("glen");
        studentsList.createNode("nomer");
        studentsList.createNode("angelo");

        //Prints the nodes-value present in the list
        studentsList.printNode();

    }
}