// Chap 7, pp 312 - 313
// Rename this file as QueueP.h

// ********************************************************
// Header file QueueP.h for the ADT queue.
// Pointer-based implementation.
// ********************************************************
#ifndef QTYPE
typedef int queueItemType;  // desired-type-of-queue-item
#define QTYPE
#endif

struct queueNode;  // defined in implementation file
typedef queueNode* ptrType;  // pointer to node

#include "boolean.h"

class queueClass
{
public:
// constructors and destructor:
   queueClass();                     // constructor
   queueClass(const queueClass& Q);  // copy constructor
   ~queueClass();                    // destructor

// queue operations:
   boolean QueueIsEmpty();
   // Determines whether a queue is empty.
   // Precondition: The constructor has been called.
   // Postcondition: Returns TRUE if the queue was empty,
   // otherwise returns FALSE.

   void QueueAdd(queueItemType NewItem, boolean& Success);
   // Adds an item to the rear of a queue.
   // Precondition: NewItem is the item to be added. The
   // constructor has been called.
   // Postcondition: If insertion was successful, NewItem
   // is at the rear of the queue and Success is TRUE;
   // otherwise Success is FALSE.

   void QueueRemove(boolean& Success);
   // Removes the item at the front of a queue.
   // Precondition: The constructor has been called.
   // Postcondition: If the queue was not empty, the item
   // that was added to the queue earliest is removed and
   // Success is TRUE. However, if the queue was empty,
   // removal is impossible and Success is FALSE.

   void GetQueueFront(queueItemType& QueueFront,
		      boolean& Success);
   // Retrieves the item at the front of a queue.
   // Precondition: The constructor has been called.
   // Postcondition: If the queue was not empty, QueueFront
   // contains the item that was added to the queue earliest
   // and Success is TRUE. However, if the queue was empty,
   // the operation fails, QueueFront is unchanged, and
   // Success is FALSE. The queue is unchanged.

private:
   ptrType Rear;
};  // end class
// End of header file.