/**

* A class that implements the ADT queue by using an expandable circular array

* with one unused location.

*

*/

public class ArrayQueue implements QueueInterface {

private T[] queue; // circular array of queue entries and one unused location

private int frontIndex;

private int backIndex;

private static final int DEFAULT_INITIAL_CAPACITY = 50;

public ArrayQueue() {

this(DEFAULT_INITIAL_CAPACITY);

}

public ArrayQueue(int initialCapacity) {

queue = (T[]) new Object[initialCapacity + 1];

frontIndex = 0;

backIndex = initialCapacity;

}

public void enqueue(T newEntry) {

if (isArrayFull())

doubleArray();

backIndex = (backIndex + 1) % queue.length;

queue[backIndex] = newEntry;

}

public T getFront() {

T front = null;

if (!isEmpty())

front = queue[frontIndex];

return front;

}

public T dequeue() {

T front = null;

if (!isEmpty()) {

front = queue[frontIndex];

queue[frontIndex] = null;

frontIndex = (frontIndex + 1) % queue.length;

}

return front;

}

public boolean isEmpty() {

return frontIndex == ((backIndex + 1) % queue.length);

}

public void clear() {

if (!isEmpty()) { // deallocates only the used portion

for (int index = frontIndex; index != backIndex; index = (index + 1)

% queue.length) {

queue[index] = null;

}

queue[backIndex] = null;

}

frontIndex = 0;

backIndex = queue.length - 1;

}

private boolean isArrayFull() {

return frontIndex == ((backIndex + 2) % queue.length);

}

private void doubleArray() {

T[] oldQueue = queue;

int oldSize = oldQueue.length;

queue = (T[]) new Object[2 * oldSize];

for (int index = 0; index < oldSize - 1; index++) {

queue[index] = oldQueue[frontIndex];

frontIndex = (frontIndex + 1) % oldSize;

}

frontIndex = 0;

backIndex = oldSize - 2;

}

public void display() {

for(int i=frontIndex; i!=(backIndex+1)%queue.length; i=(i+1)%queue.length) {

T data = queue[i];

System.out.print(data + " ");

}

System.out.println();

}

public void splice(ArrayQueue anotherQueue) {

// YOUR CODE HERE

}

}

Question: Show the contents of two initially empty queues after each of the following statements execute. Assume a, b, x, and y are objects.

Your answer should have 11 lines that each show the contents of q1 and q2.

Put the front of the queue on the left and the back of the queue on the right.

q1.enqueue(x)

q1.enqueue(y)

q2.enqueue(a)

q2.enqueue(b)

q1.enqueue(q2.getFront())

q2.enqueue(q1.dequeue())

q2.enqueue(q1.getFront())

q2.dequeue()

q1.enqueue(q2.getFront());

q1.enqueue(q1.dequeue());

q2.enqueue(q1.getFront());