// Test Driver for Queue CopyNth as a client function

#include <iostream>
// #include "queuearray.h"  // to test array implementation
#include "queuell.h"     // to test using linked implementation
using namespace std;

//----------------------------------------------------------------------
// CopyNth shows copy of Nth item from top of queue, front being item #1
//----------------------------------------------------------------------
// Accepts:  reference to queue to look at
//           N - logical position of desired item
// Returns:  copy of item at Nth position from front
//----------------------------------------------------------------------

// CopyNth as a client of the QueueType Class
void CopyNth (QueueType<char>& aqueue, int N, char& copyitem)
{
    QueueType<char> tempqueue;		// a queue for temp storage of values
    char tmp;				// temp. pointer to values

    if(!aqueue.IsEmpty())		// So long as you're not trying to 
    {					//  find a value in an empty queue...
        for(int i=0; i < N-1; i++)	// Until the Nth value is at the top
        {				//  of aqueue...
            aqueue.Dequeue(tmp);	//  dequeue from aqueue and
            tempqueue.Enqueue(tmp);	//  store in order in tempqueue.
        }
    
        aqueue.Dequeue(copyitem);	// Copy the Nth value by dequeueing
        tempqueue.Enqueue(copyitem);	//  enqueueing into tempqueue.

	while(!aqueue.IsEmpty())	// Then copy the rest of the queue 
	{				//  in order into tempqueue (so that
	    aqueue.Dequeue(tmp);	//  the line remains in it's original
	    tempqueue.Enqueue(tmp);	//  order)...
	}

	while(!tempqueue.IsEmpty())	//  and then copy the whole line back
	{				//  into aqueue with the order intact
	    tempqueue.Dequeue(tmp);
	    aqueue.Enqueue(tmp);
	}

    }
    else 
        cout << "Error - Trying to view an item in an empty stack";    
    
}
  
//--------------------------- Main function ----------------------------

int main ()
{

QueueType<char> chqueue;  // test queue

char copych;              // holds character viewed by CopyNth

// Enqueue some items

chqueue.Enqueue ('A');
chqueue.Enqueue ('B');
chqueue.Enqueue ('C');
chqueue.Enqueue ('D');
chqueue.Enqueue ('E');

// Do some CopyNth calls - queue has 5 values

cout << "\nTesting CopyNth for queue with 5 items";

CopyNth (chqueue, 5, copych);
cout << "\n\nThe 5th value should be E and it is " << copych;

CopyNth (chqueue, 1, copych);
cout << "\n\nThe 1st value should be A and it is " << copych;

CopyNth (chqueue, 3, copych);
cout << "\n\nThe 3rd value should be C and it is " << copych;

//  Dequeue 4 items, then Enqueue 3 more

chqueue.Dequeue (copych);
chqueue.Dequeue (copych);
chqueue.Dequeue (copych);
chqueue.Dequeue (copych);
chqueue.Enqueue ('F');
chqueue.Enqueue ('G');
chqueue.Enqueue ('H');

//  Do some CopyNth calls

CopyNth (chqueue, 4, copych);
cout << "\n\nThe 4th value should be H and it is " << copych;

CopyNth (chqueue, 3, copych);
cout << "\n\nThe 3rd value should be G and it is " << copych;

CopyNth (chqueue, 2, copych);
cout << "\n\nThe 2nd value should be F and it is " << copych;

CopyNth (chqueue, 1, copych);
cout << "\n\nThe 1st value should be E and it is " << copych;

chqueue.Dequeue (copych);
chqueue.Dequeue (copych);
chqueue.Dequeue (copych);
chqueue.Dequeue (copych);

// Queue should now be empty

if (chqueue.IsEmpty())
   cout << "\n\nQueue is empty, as it should be\n\n";
else
   cout << "\n\nQueue isn't empty, but should be - uh-oh!\n\n";

return 0;

}