Question

Your Task:

Starting with the following generic classes:

public class LinkedListNode<E>

{

public E element;

public LinkedListNode<E> next;

}

public class LinkedListBox<E>

{

public LinkedListNode<E> head;

public int count = 0;

}

Create a LINKED LIST of random integers between 1 and 20. The program must prompt the user for the number of random integers to create before creating the list (i.e: if user asks for 40 integers then the program will link 40 integers between 1 and 20 generated at random).

Once this link is created:

1. Display the linked list. [4 marks]

2. Modify the linked list by removing all EVEN numbers from the list. [6 marks]

3. Redisplay the linked list.

Sample Output:

How many integers for the list? 5

LINKED-LIST with odd and even random numbers:

-->1-->6-->7-->4-->17

LINKED-LIST with even numbers removed:

-->1-->7-->17

(Please also give comments)

Answer 1

Below is the solution:

import java.util.*;

class LinkedListNode<E>
{
public E element;
public LinkedListNode<E> next;
}
class LinkedListBox<E>
{
public LinkedListNode<E> head;
public int count = 0;
}

public class Main
{
   public static void main(String[] args) {
   int number = 0;
   LinkedListNode<Integer> node = null;
   LinkedListBox<Integer> myLinkedList = new LinkedListBox<Integer>();;
   LinkedListNode lastNode = null;
     
   int max = 20; int min = 1;
   System.out.println("Enter the number of random integers to create");
  
   Scanner sc = new Scanner(System.in);
   number = sc.nextInt();

//Random number generation code

   for(int i=0; i < number; i++){
   node = new LinkedListNode<Integer>();
  
   int element = (int)(Math.random()*(max-min+1)+min);
   node.element = element;
   node.next = null;

//Checking if the head is present or not

       if (myLinkedList.head == null){
       myLinkedList.head = node;
       myLinkedList.count++;
       //lastNode = node;
       }
       else{
       LinkedListNode tmpNode = myLinkedList.head;
   while(tmpNode.next != null){
   tmpNode = tmpNode.next;
   }
   tmpNode.next = node;
   myLinkedList.count++;
       }
      
   }
  
   System.out.println("Displaying the Linked List : ");
   LinkedListNode tmpNode = myLinkedList.head;
//looping through the List and printing the elements

while(tmpNode.next != null){
   System.out.print(tmpNode.element + "->");
   tmpNode = tmpNode.next;
   }
   System.out.println(tmpNode.element);
     

  
   System.out.println("Removing the even numbers from Linked List ");
   tmpNode = myLinkedList.head;
LinkedListNode prevNode = null;

//Checking if the head value is even or not
while(tmpNode != null && (Integer)tmpNode.element % 2 == 0){
   myLinkedList.head = tmpNode.next;
   tmpNode = tmpNode.next;
   }
  
   tmpNode = tmpNode.next;
prevNode = myLinkedList.head;
  
while (tmpNode != null )
{

//checking the node value is even or not
if ((Integer)tmpNode.element % 2 != 0){
prevNode = tmpNode;
tmpNode = tmpNode.next;
}
else {

//Removing the node if the value is even.
prevNode.next = tmpNode.next;
tmpNode = tmpNode.next;
}
}

System.out.println("Displaying the Linked Listafter removing the even elements : ");
   tmpNode = myLinkedList.head;
   while(tmpNode.next != null){

//printing the values after removing the even numbers.
   System.out.print(tmpNode.element + "->");
   tmpNode = tmpNode.next;
   }
   System.out.println(tmpNode.element);
   }
}