#ifndef LISTITERATOR_H
#define LISTITERATOR_H


//*****************************************************************************
//
//			ListIterator.h
//
//*****************************************************************************
//
//      Copyright (C) 1996 
//
//                      Ronald A. MacCracken
//			Graduate Student
//                      Computer Science Department
//                      University of California
//                      Davis, CA  95616
//
//      Permission is granted to use at your own risk and 
//      distribute this software in source and binary forms 
//      provided the above copyright notice and this paragraph 
//      are preserved on all copies.  This software is provided 
//      "as is" with no express or implied warranty.
//
//*****************************************************************************

//*****************************************************************************
//
// Iterators are a special type of class in C++. They allow the programmer
// to access elements of a particular data type without having to know
// the implementation of that data type. In this case, the ListIterator
// gives the programmer access to every element in the singly-linked
// List from head to tail. If this was a doubly-linked List, it would
// probably be nice to also have an iterator going from tail to head.
//
// The example below shows how easy it is to access every element of the
// List. Also notice that no matter how the List is implemented, either
// using pointers, a dynamically allocated array like DynArray, or others,
// this code will always stay the same - so long as the appropriate changes
// are made internally to the ListIterator class. 
//
// Example Usage:
//
//	List<int>	list ;
//
//	...
//
//	for ( ListIterator<int> i ( list ) ; ! i.Is_Done ( ) ; ++i )
//	{
//	    int element = i.Get_Current ( ) ;
//
//	    ...
//	}
//
//*****************************************************************************

#include "List.h"
#include "ListElement.h"

template<class TYPE>
class ListIterator
{

private:

    ListElement<TYPE>*	first_element ;
    ListElement<TYPE>*	current_element ;
 

private:

    void		Copy   ( const ListIterator<TYPE>& ) ;
    void		Delete ( void ) ;


public:
 
			// constructors

			ListIterator ( void ) ;


			// initialize the current element to be
			// x elements into the list l

			ListIterator ( const List<TYPE>& l , const int x = 0 ) ;


			// copy constructor

			ListIterator ( const ListIterator<TYPE>& l ) ;


			// destructor

			~ListIterator ( void ) ;
 

			// assignment operator

    ListIterator<TYPE>&	operator= ( const ListIterator<TYPE>& l ) ;


			// advances current element

    ListIterator<TYPE>&	operator++ ( void ) ;
    ListIterator<TYPE>&	operator++ ( int  ) ;


			// access current element

    const TYPE&		Get_Current ( void ) const ;
 

			// accesses next element

    const TYPE&		Get_Next ( void ) const ;


			// tells whether or not iterator is finished

    int			Is_Done ( void ) const ;


			// resets current element to first element

    void		Reset ( void ) ;


			// resets current element as in constructor

    void		Reset ( const List<TYPE>& l , const int x = 0 ) ;

} ;

#include "ListIterator.C"

#endif