programming-examples/c++/Others/LinkedList.h - Header file for linked list.cpp
2019-11-15 12:59:38 +01:00

104 lines
3.4 KiB
C++

LinkedList.h - Header file for linked list
#ifndef LinkedList_H
#define LinkedList_H
#include "dsexceptions.h"
#include <iostream.h> // For NULL
// List class
//
// CONSTRUCTION: with no initializer
// Access is via ListItr class
//
// ******************PUBLIC OPERATIONS*********************
// boolean isEmpty( ) --> Return true if empty; else false
// void makeEmpty( ) --> Remove all items
// ListItr zeroth( ) --> Return position to prior to first
// ListItr first( ) --> Return first position
// void insert( x, p ) --> Insert x after current iterator position p
// void remove( x ) --> Remove x
// ListItr find( x ) --> Return position that views x
// ListItr findPrevious( x )
// --> Return position prior to x
// ******************ERRORS********************************
// No special errors
template <class Object>
class List; // Incomplete declaration.
template <class Object>
class ListItr; // Incomplete declaration.
template <class Object>
class ListNode
{
ListNode( const Object & theElement = Object( ), ListNode * n = NULL )
: element( theElement ), next( n ) { }
Object element;
ListNode *next;
friend class List<Object>;
friend class ListItr<Object>;
};
template <class Object>
class List
{
public:
List( );
List( const List & rhs );
~List( );
bool isEmpty( ) const;
void makeEmpty( );
ListItr<Object> zeroth( ) const;
ListItr<Object> first( ) const;
void insert( const Object & x, const ListItr<Object> & p );
ListItr<Object> find( const Object & x ) const;
ListItr<Object> findPrevious( const Object & x ) const;
void remove( const Object & x );
const List & operator=( const List & rhs );
private:
ListNode<Object> *header;
};
// ListItr class; maintains "current position"
//
// CONSTRUCTION: Package friendly only, with a ListNode
//
// ******************PUBLIC OPERATIONS*********************
// bool isPastEnd( ) --> True if past end position in list
// void advance( ) --> Advance (if not already null)
// Object retrieve --> Return item in current position
template <class Object>
class ListItr
{
public:
ListItr( ) : current( NULL ) { }
bool isPastEnd( ) const
{ return current == NULL; }
void advance( )
{ if( !isPastEnd( ) ) current = current->next; }
const Object & retrieve( ) const
{ if( isPastEnd( ) ) throw BadIterator( );
return current->element; }
private:
ListNode<Object> *current; // Current position
ListItr( ListNode<Object> *theNode )
: current( theNode ) { }
friend class List<Object>; // Grant access to constructor
};
#include "LinkedList.cpp"
#endif