Write a testing class that is similar to linkedListApplication class defined in p2-1 to test program p2-2 DoubleLinkedList. Make sure that you understand each operation in the program.

import java.util.*;

public final class linkedListApplication

{

public static void main(String args[])

{

int Key, preKey;

int NewItem;

/* create an empty linked list */

LinkedList LL = new LinkedList();

/* create a linked list of 5 nodes */

Random rnd = new Random();

for (int i = 0; i < 5; i++)

{

NewItem = rnd.nextInt(101) ;

LL.Append(NewItem);

}

/* print the list */

System.out.println("The following are the items/integers in the current linked list from the header:");

// LL.PrintList();

LL.ShowLinkedList();

System.out.println("Enter 1 for search, 2 for insertion, 3 for deletion, 4 for append, 5 for remove, 6 for exit");

int s = Integer.parseInt(new Scanner(System.in).nextLine());

while (s == 1 || s == 2 || s == 3 || s == 4 || s == 5)

{

if (s == 1)

{

System.out.println("Enter an key/integer that you want to search:");

Key = Integer.parseInt(new Scanner(System.in).nextLine());

Node n = LL.Search(Key);

if (n != null)

{

System.out.printf("The item/integer is found: %1$s" + " ", n.item);

}

else

{

System.out.println("there is no such key!");

}

};

if (s == 2)

{

System.out.println("Enter a new item/integer that you want to insert:");

NewItem = Integer.parseInt(new Scanner(System.in).nextLine());

System.out.println("Enter the preKey/integer that the new item will follow:");

preKey = Integer.parseInt(new Scanner(System.in).nextLine());

LL.Insert(NewItem, preKey);

System.out.println("The items/integers of the current linked list from the header:");

LL.ShowLinkedList();

};

if (s == 3)

{

System.out.println("Enter the key/integer of the item that you want to delete:");

Key = Integer.parseInt(new Scanner(System.in).nextLine());

LL.Delete(Key);

System.out.println("The items/integers in the current linked list from the header.");

LL.ShowLinkedList();

};

if (s == 4)

{

System.out.println("Enter the item/integer that you want to append:");

NewItem = Integer.parseInt(new Scanner(System.in).nextLine());

LL.Append(NewItem);

System.out.println("The items/integers in the current linked list from the header");

LL.ShowLinkedList();

};

if (s == 5)

{

Node RemoveNode = LL.Remove();

if (RemoveNode != null)

{

System.out.printf("The removed item is: %1$s" + " ", RemoveNode.item);

System.out.println("The items/integers in the current linked list from the header");

LL.ShowLinkedList();

}

else

{

System.out.println("The linked list is empty!");

}

};

System.out.println(" ");

System.out.println("Enter 1 for search, 2 for insertion, 3 for deletion, 4 for append, 5 for remove");

s = Integer.parseInt(new Scanner(System.in).nextLine());

}

System.out.println("Goodbye!");

}

}