Question

JAVA

you have been given the code for Node Class (that holds Strings) and the LinkedList Class (some methods included). Remember, you will use the LinkedList Class that we developed in class not Java’s LinkedList Class. You will add the following method to the LinkedList Class:

printEvenNodes – this is a void method that prints Nodes that have even indices (e.g., 0, 2, 4, etc).

Create a LinkedListDemo class. Use a Scanner Class to read in city names and store each name in the LinkedList by adding to the front of the list. Read in names until * is entered.
Print out the LinkedList.

Details

Sample Input
Truro Halifax Pictou Trinty Moncton *

Sample Output
Moncton–>Trinty–>Pictou–>Halifax–>Truro–>
Even nodes:
Moncton–>Pictou–>Truro–>

//class LinkedList (only the first few methods are given here)
public class LinkedList{
private Node front;
private int count;
//constructor
public LinkedList(){
front = null;
count = 0;
}
//add a node to the front of the linked list
public void addToFront(String d){
Node n;
n = new Node(d, front);
front = n;
count++;
}

//get the current size of the list
public int size(){ return count; }
//check if the list is empty
public boolean isEmpty(){ return (count==0); }
//clear the list
public void clear(){
front = null;
count=0;
}
//get the content of the first node
public String getFrontData() {
if (front==null)
return "Empty list";
else
return front.getData();
}
//new method added - get the first node
public Node getFront() {
return front;
}
//scan the list and print contents
public void enumerate() {
Node curr = front;
while (curr!=null) {
System.out.print(curr);
curr = curr.getNext();
}

}
//ADD NEW METHOD
  
}

Answer 1

import java.util.Scanner;

class LinkedList {
   private Node front;
   private int count;

   // constructor
   public LinkedList() {
       front = null;
       count = 0;
   }

   // add a node to the front of the linked list
   public void addToFront(String d) {
       Node n;
       n = new Node(d, front);
       front = n;
       count++;
   }

   // get the current size of the list
   public int size() {
       return count;
   }

   // check if the list is empty
   public boolean isEmpty() {
       return (count == 0);
   }

   // clear the list
   public void clear() {
       front = null;
       count = 0;
   }

   // get the content of the first node
   public String getFrontData() {
       if (front == null)
           return "Empty list";
       else
           return front.getData();
   }

   // new method added - get the first node
   public Node getFront() {
       return front;
   }

   // scan the list and print contents
   public void enumerate() {
       Node curr = front;
       while (curr != null) {
           System.out.print(curr);
           curr = curr.getNext();
       }

   }
   // ADD NEW METHOD removeMiddle

   public void printsEvenNodes(){
       Node curr = front;
       while (curr != null) {
           //prints current node data
           System.out.print(curr);
           //moving to next node
           curr = curr.getNext();
           // if is it not last node, go to even node
           if(curr!=null)
               curr=curr.getNext();
       }
   }
}

// class Node
class Node {
   private String data;
   private Node next;

   public Node(String d, Node n) {
       data = d;
       next = n;
   }

   public String getData() {
       return data;
   }

   public Node getNext() {
       return next;
   }

   public void setData(String d) {
       data = d;
   }

   public void setNext(Node n) {
       next = n;
   }

   public String toString() {
       return data + "-->";
   }
}

public class LinkedListDemo {
   public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
       LinkedList list = new LinkedList();
       while(true){
           System.out.println("Enter name");
           String s =sc.nextLine();
           if(s.equals("*"))
               break;
       list.addToFront(s);
       }
          
       // printing the list
       System.out.println();
       list.enumerate();
       System.out.println("\nEven Nodes : ");
       list.printsEvenNodes();
   }
}