Question

USING JAVA LANGUAGE : Using Doubly Linked List, create a java code that does the following Without using LinkedList from the JAVA LIBRARY. and please include methods for each function.

Create a menu that contains the following operations :

1. Add new node to DLL. ( as a METHOD )

2. Delete a node from DLL. ( as a METHOD )

3. Show how many nodes in DLL. ( as a METHOD )

4. Print all data in the DLL. ( as a METHOD )

5. Exit.

Important notes :

1. Write the operations from the pseudocode.

2. The user should insert all data even in the first node.

3. The menu should be repeated each time until the user 5 (Exit).

Answer 1

***For deleting node function I have implemented delete of first node as in your it was not mentioned.

***If you want to modify it you can comment so that I can update it.

***And If it works please like it. It takes lots oof effort to coding Question.

-------------------------------------------------------------------------------------------------------------------------------

Code:

import java.util.*;

public class Main {
   Node head;
  
   class Node {
       int data;
       Node prev;
       Node next;

       Node(int d) { data = d; }
   }

   public void push(int nd)
   {
      
       Node nn = new Node(nd);
       nn.next = head;
       nn.prev = null;

       if (head != null)
           head.prev = nn;

       head = nn;
   }
  
void deleteNode(Node dd)
{
if (head == null || dd == null) {
return;
}
if (head == dd) {
head = dd.next;
}
if (dd.next != null) {
dd.next.prev = dd.prev;
}
if (dd.prev != null) {
dd.prev.next = dd.next;
}
return;
}

   public void printlist(Node nn)
   {
       System.out.println("Elements in DLL : ");
       while (nn != null) {
           System.out.print(nn.data + " ");
           nn = nn.next;
       }
       System.out.println(" ");
      
   }
   public int countlist(Node nn)
   {
   int c = 0;
   while (nn != null) {
           c++;
           nn = nn.next;
       }
       return c;
   }
   public static void main(String[] args)
   {
       Main dll = new Main();
       boolean flag = true;
       while(flag){
       int x;
       System.out.println("1. Add new node to DLL.\n2. Delete a node from DLL.\n3. Show how many nodes in DLL.\n4. Print all data in the DLL.\n5. Exit.");
       Scanner sc = new Scanner(System.in);
       x = sc.nextInt();
       switch(x)
       {
       case 1:
       System.out.println("Enter the data to be inserted: ");
       int y1 = sc.nextInt();
       dll.push(y1);
       System.out.println("Data inserted!");
       System.out.println(" ");
       break;
       case 2:
       dll.deleteNode(dll.head);
       System.out.println("Data Deleted!");
       System.out.println(" ");
       break;
       case 3:
       System.out.println("Number of nodes in DLL: " + dll.countlist(dll.head));
       System.out.println(" ");
       break;
       case 4:
       System.out.println("Created DLL is: ");
       dll.printlist(dll.head);
       System.out.println(" ");
       break;
       case 5:
       flag = false;
       break;
       default:
       System.out.println("Wrong Input!");
       System.out.println(" ");
      
       }
       }
   }
}

------------------------------------------------------------------------------------------------------------------------------------

Output screenshots and Code screenshots

------------------------------------------------------------------------------------------------------------------------------------