programming-examples/c++/Others/LinkedList.cpp - Implementation for linked list.cpp

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2019-11-15 12:59:38 +01:00
LinkedList.cpp - Implementation for linked list
#include "LinkedList.h"
/**
* Construct the list
*/
template <class Object>
List<Object>::List( )
{
header = new ListNode<Object>;
}
/**
* Copy constructor
*/
template <class Object>
List<Object>::List( const List<Object> & rhs )
{
header = new ListNode<Object>;
*this = rhs;
}
/**
* Destructor
*/
template <class Object>
List<Object>::~List( )
{
makeEmpty( );
delete header;
}
/**
* Test if the list is logically empty.
* return true if empty, false otherwise.
*/
template <class Object>
bool List<Object>::isEmpty( ) const
{
return header->next == NULL;
}
/**
* Make the list logically empty.
*/
template <class Object>
void List<Object>::makeEmpty( )
{
while( !isEmpty( ) )
remove( first( ).retrieve( ) );
}
/**
* Return an iterator representing the header node.
*/
template <class Object>
ListItr<Object> List<Object>::zeroth( ) const
{
return ListItr<Object>( header );
}
/**
* Return an iterator representing the first node in the list.
* This operation is valid for empty lists.
*/
template <class Object>
ListItr<Object> List<Object>::first( ) const
{
return ListItr<Object>( header->next );
}
/**
* Insert item x after p.
*/
template <class Object>
void List<Object>::insert( const Object & x, const ListItr<Object> & p )
{
if( p.current != NULL )
p.current->next = new ListNode<Object>( x, p.current->next );
}
/**
* Return iterator corresponding to the first node containing an item x.
* Iterator isPastEnd if item is not found.
*/
template <class Object>
ListItr<Object> List<Object>::find( const Object & x ) const
{
/* 1*/ ListNode<Object> *itr = header->next;
/* 2*/ while( itr != NULL && itr->element != x )
/* 3*/ itr = itr->next;
/* 4*/ return ListItr<Object>( itr );
}
/**
* Return iterator prior to the first node containing an item x.
*/
template <class Object>
ListItr<Object> List<Object>::findPrevious( const Object & x ) const
{
/* 1*/ ListNode<Object> *itr = header;
/* 2*/ while( itr->next != NULL && itr->next->element != x )
/* 3*/ itr = itr->next;
/* 4*/ return ListItr<Object>( itr );
}
/**
* Remove the first occurrence of an item x.
*/
template <class Object>
void List<Object>::remove( const Object & x )
{
ListItr<Object> p = findPrevious( x );
if( p.current->next != NULL )
{
ListNode<Object> *oldNode = p.current->next;
p.current->next = p.current->next->next; // Bypass deleted node
delete oldNode;
}
}
/**
* Deep copy of linked lists.
*/
template <class Object>
const List<Object> & List<Object>::operator=( const List<Object> & rhs )
{
ListItr<Object> ritr = rhs.first( );
ListItr<Object> itr = zeroth( );
if( this != &rhs )
{
makeEmpty( );
for( ; !ritr.isPastEnd( ); ritr.advance( ), itr.advance( ) )
insert( ritr.retrieve( ), itr );
}
return *this;
}