Question

in C++ creat a DynamicQueue class, add a new data member called count to trace the total number of node you have in current queue (you need to modify some member functions for adding count). Add a member function called displayQueue() to display values stored in each node in the current queue, also the total number of nodes in the queue. You also need to have a driver program (refer to Tester) to test your modified new class and new member function.

// This program demonstrates the DynamicQueue template.
#include <iostream>
#include <string>
#include "DynamicQueue.h"
using namespace std;

const int QUEUE_SIZE = 5;

int main()
{
    string name;
    
    // Create a Queue.
    DynamicQueue<string> queue;
    
    // Enqueue some names.
    for (int count = 0; count < QUEUE_SIZE; count++)
    {
        cout << "Enter an name: ";
        getline(cin, name);
        queue.enqueue(name);
    }
    
    // Dequeue the names and display them.
    cout << "\nHere are the names you entered:\n";
    for (int count = 0; count < QUEUE_SIZE; count++)
    {
        queue.dequeue(name);
        cout << name << endl;
    }
    return 0;
}

Answer 1

CODE:

Please include the below files in the same folder where you have the file having main() function.

DynamicQueue.h

#ifndef DynamicQueue_H
#define DynamicQueue_H
#include <iostream>

using namespace std;
#pragma once

template <class T>
class DynamicQueue
{
private:
   //Struct for nodes
   struct Node
   {
       T data;   
       Node *next;   
   };

   Node *front; //front of the queue
   Node *back; //back of the queue

   int numberOfNodes; //Tracks number of nodes in queue

public:

   //Constructor
   DynamicQueue();

   void enqueue(T);
   void dequeue(T &);
   bool isEmpty() const;
   void displayQueue();
   void destroyQueue();
  
   //Destructor
   ~ DynamicQueue();
};
#endif

--------------------------------------------------------------------------------
DynamicQueue.cpp

#include <iostream>
#include <string>
#include "DynamicQueue.h"

using namespace std;

template <class T>
DynamicQueue<T>:: DynamicQueue()
{
   front = NULL;
   back = NULL;
   numberOfNodes = 0;
}

template <class T>
void DynamicQueue<T>::enqueue(T val)
{
   Node *newNode;

   //Create new node, have it hold val
   newNode = new Node;
   newNode->data = val;
   newNode->next = NULL;

   //Change front and back pointers, depending on if the queue is empty or already contains data

   if (isEmpty())
   {
       front = newNode;
       back = newNode;
   }
   else
   {
       back->next = newNode;
       back = newNode;
   }

   //update number of nodes in queue
   numberOfNodes++;
}

template <class T>
void DynamicQueue<T>::dequeue(T &val)
{
   Node *temp;

   if(isEmpty())
   {
       cout << "No data currently queued" << endl;
   }
   else
   {
       //Store data from front node in val
       val = front->data;
       //Remove front node, delete
       temp = front;
       front = front->next;
       delete temp;

       //Update numberOfNodes
       numberOfNodes--;
   }
}

template <class T>
bool DynamicQueue<T>::isEmpty() const
{
   bool empty;

   if(numberOfNodes > 0)
       empty = false;
   else
       empty = true;
  

   return empty;
}

template <class T>
void DynamicQueue<T>::destroyQueue()
{
   T temp;

   while(!isEmpty())
   {
       dequeue(data);
   }
}

template <class T>
DynamicQueue<T>::~ DynamicQueue()
{
   destroyQueue();
}

template <class T>
void displayQueue(){
  
   if(!isEmpty())
   {
       Node *temp;
       cout << "Number of nodes in Queue are: " << numberOfNodes << endl;
       cout << "Queue Elements are: " << endl;
       temp = front;
       while(temp->next != NULL){
           cout << temp->data << endl;
           temp = temp->next;
       }
      
   }
}