Q) Modify the Queue class to include appropriate error messages if invalid conditions occurfor example, trying to dequeue an item when the queue is empty.

Code is below (main.cpp, Queue.cpp, Queue.h)

main.cpp

/*******************************

* Week 2 lesson: *

* a simple Queue class *

*******************************/

#include "Queue.h"

#include

using namespace std;

int main()

{

Queue q;

cout << "Insertion of 10 characters in q" << endl;

for(int i=0; i < q.getSize(); i++)

{

char x = 32 + rand()%95;

cout << x << endl;

q.enqueue(x);

}

cout << endl

<< "Displaying and deleting elements from q" << endl;

while(!q.isEmpty())

{

cout << "Item at the front: " << q.getFront() << endl;

q.dequeue();

}

return 0;

}

Queue.cpp

/*******************************

* Week 2 lesson: *

* a simple Queue class *

*******************************/

#include "Queue.h"

/*

* Constructor. Initializes the queue.

*/

Queue::Queue()

{

front = 0;

back = SIZE-1;

count = 0;

}

/*

* Determines whether the queue is empty.

*

* Returns true if the queue is empty, false otherwise.

*/

bool Queue::isEmpty()

{

return count == 0;

}

/*

* Adds an element to the back of the queue.

*

* x: element to be added to the queue.

*/

void Queue::enqueue(char x)

{

back = (back+1)%SIZE;

list[back] = x;

count++;

}

/*

* Removes the element in the front of the queue.

*/

void Queue::dequeue()

{

front = (front+1)%SIZE;

count--;

}

/*

* Returns the element in the front of the queue. Does not remove it.

*/

char Queue::getFront()

{

return list[front];

}

/*

* Returns the size of the queue.

*/

int Queue::getSize()

{

return SIZE;

}

Queue.h

/*******************************

* Week 2 lesson: *

* a simple Queue class *

*******************************/

/*

* Class implementing a Queue ADT.

*/

class Queue

{

public:

Queue();

bool isEmpty();

void enqueue(char);

void dequeue();

char getFront();

int getSize();

private:

static const int SIZE = 10; //size of the queue array

char list[SIZE]; //array to store the queue items

int count; //number of items in the queue

int front, back; //front and back locations

};