Question

Your text has an example of LinkedList class. Convert the class so that the Link objects have a single long instance variable -- call it "data" -- and the Link instance variable.. Step 2 Then add the following capabilities to the class. A constructor that takes an array of longs as an argument. The contents of the array are use to create Link objects that become objects in the LinkedList. A "search" method that takes a long argument and returns a boolean value. The method searches the LinkedList object for Link objects with a data value that matches the long argument. It returns a true or false based on whether or not a matching value is present in the LinkedList. A "numberOfValues" method that takes a long argument and returns an int value. The method searches the LinkedList object for Link objects with a data value that matches the long argument. It returns a numeric value that is the number of times the long argument is present in the LinkedList. A "replace" method that takes two long arguments and returns a void. The method finds all occurrences of the first long value in the Links of the LinkedList and replaces their data value with the method's second long value. A "zero" method that replaces all values in the LinkedList's Link objects with zeros. A "getArray" method that returns a long array. The method returns long array that contains the long data values in the Link objects of the LinkedList Step 3 Give the project a LinkedListDriver class that contains your main method. Instantiate a LinkedList object, using the array constructor. Demonstrate the isEmpty, insertFirst, deleteFirst, and displayList methods. Also demonstrate the methods from Step 2. Remember that your output should clearly state what you are doing in your code.

Answer 1

// --------------------- LinkedListDriver.java ---------------------------

public class LinkedListDriver {

public static void main(String[] args) {

Long[] values = {9l, 2l, 6l, 9l, 3l};

Long newElement = 5l;

LinkedListModified linkedList = new LinkedListModified(values);

System.out.print("Initial List : ");

linkedList.displayList();

System.out.println();

System.out.println("Linked List : is emplty : "+linkedList.isEmpty() + "\n");

linkedList.insertFirst(newElement);

System.out.println("Linked List after adding new element ["+newElement+"] at first");

linkedList.displayList();

System.out.println();

linkedList.deleteFirst();

System.out.println("Linked List after deleting first element : ");

linkedList.displayList();

System.out.println();

System.out.println("Searching element : Is element [3] exists ? : "+linkedList.search(3l) + "\n");

System.out.println("Counting existance of element : How many times element [9] exists ? : "+linkedList.numberOfValues(9l) + "\n");

linkedList.replace(9l, 8l);

System.out.println("Linked list after replacing element [9] with element [8]:");

linkedList.displayList();

System.out.println();

linkedList.zero();

System.out.println("Linked list after setting all to zero:");

linkedList.displayList();

System.out.println();

}

}

// --------------- LinkedListModified.java -----------------------

import collection.linkedlist.LLNode;

public class LinkedListModified {

protected LLNode<Long> head; // First node

protected LLNode<Long> tail; // First node

protected int listSize; // Size of LinkedList

public LinkedListModified(Long[] values) {

this.head = null;

this.listSize = 0;

for(Long value : values) {

LLNode<Long> newNode = new LLNode<Long>(value);

if (head == null)

{

this.head = newNode;

this.tail = head;

} else {

this.tail.setLink(newNode);

this.tail = newNode;

}

this.listSize++;

}

}

public boolean search(Long element) {

LLNode<Long> location = head;

boolean found = false;

while (location != null) {

// if they match

if (location.getData().equals(element)) {

found = true;

break;

}

location = location.getLink();

}

return found;

}

public int numberOfValues(Long element) {

LLNode<Long> location = head;

int count = 0;

while (location != null) {

if (location.getData().equals(element)) {

count++;

}

location = location.getLink();

}

return count;

}

public void replace(Long source, Long target) {

LLNode<Long> location = head;

while (location != null) {

// if they match

if (location.getData().equals(source)) {

location.setData(target);

} else {

location = location.getLink();

}

}

}

public void zero() {

LLNode<Long> location = head;

while (location != null) {

location.setData(0l);

location = location.getLink();

}

}

public Long[] getArray() {

Long[] elements = new Long[listSize];

LLNode<Long> location = head;

int index = 0;

while (location != null) {

elements[index]=location.getData();

location = location.getLink();

index++;

}

return elements;

}

public boolean isEmpty() {

return listSize == 0;

}

public void insertFirst(Long element) {

LLNode<Long> newNode = new LLNode<Long>(element);

if(head == null) {

head = newNode;

} else {

newNode.setLink(head);

head = newNode;

}

}

public void deleteFirst() {

if(head == null) {

return;

} else {

head = head.getLink();

}

}

public void displayList() {

LLNode<Long> location = head;

while (location != null) {

System.out.print("["+location.getData() + "]" + " --> ");

location = location.getLink();

}

System.out.println("NULL");

}

}

// Sample output below

Initial List : [9]-2] --> [6] --> [9] --> [3] --> NULL Linked List : is emplty : false Linked List after adding new element [5] at first 5] -- 9] --> 2] > [6] --> [9] --> [3] --> NULL Linked List after deleting first element: 19] -> [2] --> [6] --> [9] --> [3] --> NULL Searching element : Is element [3] exists ? : true Counting existance of element How many times element [9] exists ? : 2 Linked list after replacing element [9] with element [8]: [8] --> [2] --〉 [6] --> [8] --> [3] --> NULL Linked list after setting all to zero: [0] -> [0] --> [0] --> [0]--> [0] --> NULL