1 Implement the portions of Node and List that we have cover

1) Implement the portions of Node and List that we have covered in class. Both classes should be in YOUR personal package we used for Die. The APls for both are shown below: Node Class Constructors Node() Node(int v) Node(int v, Node n) Accessors int getValue() Node getNext() Mutators void setValue( int v) void setNext( Node n ) Additional String toString) LinkedList Class Constructors LinkedList() Mutators void append( int x) Accessors int valueAt( int pos) 2) Write a test program for each class. The program should test out the class to show that it is working correctly. For example, with Node, you will need to show that you can create multiple Nodes and link them together using the methods provided.

Solution

Note : I have modified the method valueAt() of linklist class. The method which appeared in the question was not correct. And i have also included check for wrong input.

import java.util.NoSuchElementException;

class Node {
   private int value;
   private Node next;

   //Constructors
   public Node() {
       value = 0;
       next = null;
   }

   public Node(int v) {
       value = v;
       next = null;
   }

   public Node(int v, Node n) {
       value = v;
       next = n;
   }

   // Accessors
   public int getValue() {
       return value;
   }

   public Node getNext() {
       return next;
   }

   // mutators
   public void setValue(int value) {
       this.value = value;
   }

   public void setNext(Node next) {
       this.next = next;
   }

   // Additional
   @Override
   public String toString() {
       return \"Node: \" + value;
   }

}

class LinkList {
   private Node start, end;
   private int size;
//Constructors
   public LinkList() {
       start = null;
       end = null;
       size = 0;
   }

   //Mutators
   public void append(int x) {
       if (size == 0) {
           start = new Node(x);
           end = start;
       } else {
           Node temp = new Node(x);
           end.setNext(temp);
           end = temp;
       }

       size++;
}

   public int valueAt(int i) {
       if(i<0 || i>=size){
           throw new NoSuchElementException();
       }else if (i == 0) {
           return start.getValue();
       } else if (i == size - 1) {
           return end.getValue();
       } else {
           int currentIndex = size;
           Node temp = start;
           while (i < currentIndex) {
               currentIndex--;
               temp = temp.getNext();
           }
           return temp.getValue();
       }
   }
}

public class Test {

   public static void main(String[] args) {
      
       Node node1 = new Node();
       System.out.println(node1);
       Node node2 = new Node(10);
       System.out.println(node2);
       Node node3 = new Node(20, node2);
       System.out.println(node3);
      
       LinkList linklist=new LinkList();
       linklist.append(20);
       linklist.append(40);
       linklist.append(60);
       linklist.append(80);
       System.out.println(\"value at 2nd position : \"+linklist.valueAt(2));
      
   }

}

--------------------------------------------------output-----------------------------------------------------------------

Node: 0
Node: 10
Node: 20
value at 2nd position : 60