Question

Write a Java class myLinkedList to simulate a singly linked list using arrays as the underlying structure. Include the following methods:

1. insert an element within the linked list.(this should also work for the front and the rear of the list)

2. Remove an element from the linked list

3. Display (print) the elements of the linked list in order.

4. A method to check if the list is "empty".

Test your solution using a linked list that initially has the characters A, B, D, E, F, and G. Insert "C" between B and D. Remove element "F".

[Hint: One solution (recommended) is to use 2 arrays. One for the data, and the other for the "next" pointer. Also, consider using dummy nodes for the front, and possibly the rear of the list]

Extend the solution so that it simulates a doubly linked list! (hint: You will need a third array to represent the "backward" pointers)

Answer 1

Hi Student,s

Please find below the solution of your query i.e. SIngly linkedlist implementation using Java -

1. FIrat create a Node class
class Node {
public int data;
public Node next;

public void displayNodeData() {
System.out.println("{ " + data + " } ");
}
}

2. Now Write the program to create a Singly linked list with all the operations you mentioned
package org.arpit.java2blog;

class Node {
   public int data;
   public Node next;

   public void displayNodeData() {
       System.out.println("{ " + data + " } ");
   }
}

public class SinglyLinkedList {
   private Node head;

   public boolean isEmpty() {
       return (head == null);
   }

   // used to insert a node at the start of linked list
   public void insertFirst(int data) {
       Node newNode = new Node();
       newNode.data = data;
       newNode.next = head;
       head = newNode;
   }

   // used to delete node from start of linked list
   public Node deleteFirst() {
       Node temp = head;
       head = head.next;
       return temp;
   }

   // Use to delete node after particular node
   public void deleteAfter(Node after) {
       Node temp = head;
       while (temp.next != null && temp.data != after.data) {
           temp = temp.next;
       }
       if (temp.next != null)
           temp.next = temp.next.next;
   }

   // used to insert a node at the start of linked list
   public void insertLast(int data) {
       Node current = head;
       while (current.next != null) {
           current = current.next; // we'll loop until current.next is null
       }
       Node newNode = new Node();
       newNode.data = data;
       current.next = newNode;
   }

   // For printing Linked List
   public void printLinkedList() {
       System.out.println("Printing LinkedList (head --> last) ");
       Node current = head;
       while (current != null) {
           current.displayNodeData();
           current = current.next;
       }
       System.out.println();
   }
}

3. Now let us create a driver class-

23
24

package org.arpit.java2blog;

public class LinkedListMain {

   public static void main(String args[])
   {
       SinglyLinkedList myLinkedlist = new SinglyLinkedList();
       myLinkedlist.insertFirst(5);
       myLinkedlist.insertFirst(6);
       myLinkedlist.insertFirst(7);
       myLinkedlist.insertFirst(1);
       myLinkedlist.insertLast(2);
       // Linked list will be
       // 2 -> 1 -> 7 -> 6 -> 5
       Node node=new Node();
       node.data=1;
       myLinkedlist.deleteAfter(node);
       // After deleting node after 1,Linked list will be
       // 2 -> 1 -> 6 -> 5
       myLinkedlist.printLinkedList();
   }
}
4 Output-
Printing LinkedList (head --> last)
{ 1 }
{ 6 }
{ 5 }
{ 2 }

5. Similarly you can write all your methods. If you face any concern write the same in comments.

Please hit the like button if you liked my answer.
Thanks in advance.

Regards,
Ankit Tandon