/***********************************************************************************
Engineering 3891 Advanced Structured Programming
Assignment: 4 Date Due: October 12th/2000
Name: Daryl Martin
Student #: 9713520
Username: darylm
***********************************************************************************/
#include "assign4.h"

namespace std
{
   int queue[QSIZE]; //This will declare the size of the Queue from assign4.h

   int *tail = queue; //Next open postion in the queue

   int *head = queue; //The head queue item

   status currentStatus = EMPTY; //The current status of the Queue
}
using namespace std;

/***********************************************************************************
* getStatus -- Returnns the current status of teh queue
*
* Parameters:
* None
*
* Modifies: none
*
* Returns: The current status of the queue Date: 10/12/00
***********************************************************************************/

status getStatus (void)
{
   return currentStatus;
}

/***********************************************************************************
* putQueue -- Takes a number and places it into the queue at the tail if
* their is room
*
* Parameters:
* item -- the intereger to put into the queue
*
* Modifies: none
*
* Returns: The current status of the queue Date: 10/12/00 ***********************************************************************************/

status putQueue (int item)
{

if (currentStatus == FULL)
   currentStatus = OVERFLOW; //Overflow status

   if (currentStatus != OVERFLOW) //!= OVERFLOW shows us that their is room left
{
   *tail = item;
   tail++;
   currentStatus = PENDING;

if ((tail - queue) == QSIZE)
   tail = queue; //If it went to the end go back

if (tail == head)
   currentStatus = FULL; //Move to the Head....
}

return currentStatus;
}

/***********************************************************************************
* getQueue -- This will return the value at the first element.
* If none then a zero will be returned.
*
* Parameters:
* None
*
* Modifies: none
*
* Returns: The first value of the queue. A zero if non exist Date: 10/12/00
***********************************************************************************/

int
getQueue (void)
{
int zeroTerm = 0; //In case the queue is zero

if (currentStatus == EMPTY)
   currentStatus = UNDERFLOW; //Nothign in the head. Hence the Underflow

if (currentStatus != UNDERFLOW) //If the elemet's exist at *head
{
   zeroTerm = *head;
   head++;

if (head == (queue + QSIZE))
   head = queue; //if you pass the end of the queue reset it

if (tail == head)
   currentStatus = EMPTY;

else
   currentStatus = PENDING;
}
return zeroTerm;
}