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// $Id: stacklis.h,v 1.3 2005/04/10 18:31:14 tom Exp $
#ifndef _STACK_LIST_HEADER
#define _STACK_LIST_HEADER
// Code written by Steven De Toni ACBC 11
// This header definition contains information of the construction,
// operation of a container class that holds data in linked list
// in stack form.
#include <stdio.h> // NULL Constant
#include "anyobj.h" // use Base class definition
// Structure definition used to link the items in the stack
struct ListLink
{
ListLink* pLinkedItem; // linker (pointer to next item in the list)
ANYOBJECT* pItem; // variable used to contain the data
};
class StackList : public ANYOBJECT
{
protected:
ListLink* pCurrentPos; // pointer to the end of the list
int itemCount; // number of items in list
int spaceAvailable; // used to test if memory
// is still available
public:
//#### Constructors
// Initialise internal variables.
//
StackList (void);
// Initialise variables, and place item passed in a new list
//
// Parameters:
// pItem : Pointer to the object that is will to be stored.
// Item must be of descendant ANYOBJECT.
//
StackList (ANYOBJECT* pItem);
// use the defaults here:
StackList(const StackList&);
StackList& operator=(const StackList&);
//#### Access Methods
// Places a new item in the list (i.e on the stack).
//
// Parameters:
// pItem : Pointer to the object that is will to be stored.
// Item must be of descendant ANYOBJECT.
//
// Return Values:
// int : Returns a error code value to indicate whether operation
// was successful or not.
// Value:
// 0 = No Worries, item stacked.
// -1 = Item not stacked, memory allocation failure
//
int push (ANYOBJECT* pItem);
// Removes a item from the list and returns the value contained within it
// back to the user. A NULL value is returns if there are no more items
// within the list.
//
// Return Values:
// ANYOBJECT* : Pointer to the object last object that was placed
// on the stack. Returns NULL pointer if operation
// failed.
//
ANYOBJECT* pop (void);
// Peeks at items within the linked list without removing
// them from the list.
//
// Parameters:
// int item : item number in list.
//
// Return Values:
// ANYOBJECT* : Returns NULL if operation failed, else
// pointer to the object contained at list
// number selected!
//
ANYOBJECT* peek (int item);
// Returns the number of items current being stacked.
//
// Returns Values:
// int : Num of items within queue.
//
int status (void);
// Method returns whether last operation failed due to memory allocation
// failure.
//
// Return Values:
// int : Returns 1 of two values ...
// Values:
// 0 = memory available
// -1 = Last memory allocation failed.
//
int space (void);
//#### Destructor
// Method will remove all list items from memory if they still exist,
// no garbage collection provided, or used.
//
~StackList (void);
};
#endif
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