JAVA

In this part, you will implement a resizable and generic Queue using an array. The API you must implement is described below. Do not change the names or types of any of the methods below!

NOTE: You should implement the Queue using the loop-around method described during class. If you do not, you will likely not pass the test cases!

Queue API

Queue API	constructor; creates and empty Queue with initial capacity of 1
Queue(int n)	constructor; creates an empty Queue with initial capacity of n
void enqueue(Item item)	1) adds new item to the back of the Queue; 2) double the array capacity if the Queue becomes full
Item dequeue()	1) removes and returns front item from the Queue; 2) throws EmptyQueueException if the Queue is empty; 3) reduce the array capacity by half if the size of the Queue falls below 14 full but do not make the size below the initial capacity
boolean isEmpty()	return true if the Queue is empty, false otherwise
int size()	return the size of the Queue (i.e. the number of elements currently in the Queue)
Item peek()	1) return but do not remove the front item in the Queue; 2) throws an EmptyQueueException if the Queue is empty
Item[] getArray()*	return the underlying array that contains the Queue

Note: When you resize, the front of the queue should be reset to index 0. You should not reset it when the size goes to 0.

The Queue should use a loop-around method in order to reuse open space. Here is an example of how that works. Assume the initial capacity of the array is 5. The F stands for front and the B stands for back.

I HAVE A TROUBLE WITH

Queue API

constructor; creates and empty Queue with initial capacity of 1

IN MY CODE, I GET NULL POINT EXCEPTION

public class Queue { Item[] array; int size; int rear; int front; /** * Constructor of the class. * TO DO BY STUDENT */ public Queue() { } /** * Constructor of the class with initial capacity. * TO DO BY STUDENT */ @SuppressWarnings("unchecked") public Queue(int n) { front = -1; rear = -1; size = n; this.array = (Item[]) new Object[size]; }

CAN ANYONE TELL ME WHAT IS WRONG AND PLEASE WRITE THE CODE?

THANK YOU VERY MUCH BELOW IS THE STARTER CODE

public class Queue { Item[] array; /** * Constructor of the class. * TO DO BY STUDENT */ public Queue() { } /** * Constructor of the class with initial capacity. * TO DO BY STUDENT */ public Queue(int n) { } /** * Dequeue the next item. * TO DO BY STUDENT */ public Item dequeue() throws EmptyQueueException { return null; } /** * Enqueues an item. * TO DO BY STUDENT */ public void enqueue(Item item) { return null; } /** * Returns the array with the content of the queue. * DO NOT DELETE OR MODIFY. REQUIRED FOR TESTING AND GRADING. ANY MODIFICATION OF THIS FUNCTION * WILL BE CONSIDERED ACADEMIC DISHONESTY AND PENALIZED WITH 0 FOR THE ENTIRE PROJECT. */ public Item[] getArray() { return array; } /** * Indicates whether the queue is empty or not. * TO DO BY STUDENT */ public boolean isEmpty() { return false; } /** * Peeks the next item to be dequeued. * TO DO BY STUDENT */ public Item peek() throws EmptyQueueException { return null; } /** * Returns the size of the queue. * TO DO BY STUDENT */ public int size() { return 0; }

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