JAVA

Scenario: We have a linked list containing some elements and we need to build a string of the form [3,6,4,2,4]. If the list is empty, it should output [].

Aim: Write code in Java for traversing the linked list.

Steps for Completion

1. Write a toString() method in the LinkedList class as follows:

public String toString() { // ... }

2. Use a while loop to traverse the linked list.

REQUIRED TASKS

Write the toString() method in the LinkedList class.

Use a while loop to traverse the linked list to add the nodes to print to the console. Wrap the list of nodes in opening and closing brackets separated by commas : [node1, node2, node3].

GIVEN CODE:

import java.util.Optional;

public class LinkedList { private LinkedListNode head;

public LinkedList() { head = null; }

public void addFront(V item) { this.head = new LinkedListNode<>(item, head); }

public void deleteFront() { Optional> firstNode = Optional.ofNullable(this.head); this.head = firstNode.flatMap(LinkedListNode::getNext).orElse(null); firstNode.ifPresent(n -> n.setNext(null)); }

public Optional> find(V item) { Optional> node = Optional.ofNullable(this.head); while (node.filter(n -> n.getValue() != item).isPresent()) { node = node.flatMap(LinkedListNode::getNext); } return node; }

public void addAfter(LinkedListNode aNode, V item) { aNode.setNext(new LinkedListNode<>(item, aNode.getNext().orElse(null))); }

// write your code here

public static void main(String[] args) { LinkedList list = new LinkedList(); list.addFront("Isabel"); list.addFront("Ruth"); list.addFront("Karl"); list.addFront("John"); System.out.println(list.find("Isabel")); System.out.println(list.find("Ruth")); System.out.println(list.find("Karl")); System.out.println(list.find("John")); System.out.println(list.find("James"));

list.deleteFront(); System.out.println(list.find("John")); list.addFront("Oliver"); System.out.println(list.find("Ruth")); list.addAfter(list.find("Ruth").get(), "Sam"); System.out.println(list.toString());

LinkedListNode x = new LinkedListNode<>(5, null); } }