list.cpp

数据结构的一些简单算法

//======================================================================
//                               list.cpp
//======================================================================
#include "Huffman.h"

template <class list_entry> 
list<list_entry>::list()
//constructor
{
	head  = NULL;
	count = 0;
};

template <class list_entry> 
list<list_entry>::list(list<list_entry> &copy)
//constructor
{
	head  = copy.head  ;
	count = copy.size();
};

template <class list_entry>
Node<list_entry>* list<list_entry>::set_position(int position)const
//return a point to the Node in position
//if position == 0 return head ;
//if position == 1 return NULL or head->next ;
{
	Node<list_entry>* p = head ;
	for( int i = 0 ; i < position ; i++ ) 
		p = p->next;
	return p ;
};

template <class list_entry>
int list<list_entry>::ser_position(list_entry xNode)
//to search a position for new node for add or insert
//true to add and false to insert
{
	
	Node<list_entry>* p = head;
	int num = 0;
	while( p != NULL )
	{		
		if( p->entry >= xNode ) 
		{
			return num;
		}
		p = p->next;
		num++;
	}
	return count;
};

template <class list_entry>
Error_Code list<list_entry>::insert(int position,const list_entry &xNode)
//insert a node to the position
{
	if( position < 0 || position > count )
		return Position_Range_Erro    ;
	Node<list_entry>* prev     ;
	Node<list_entry>* new_node ;
	Node<list_entry>* follow   ;
	if( position > 0 )
	{
		prev   = set_position(position - 1);
		follow = prev->next   ;
	}
	else following = head     ;
	new_node = new Node<list_entry>(xNode,follow);
	if( new_node == NULL )
		return Overflow   ;
	if( position == 0 )
		head = new_node   ;
	else
		prev->next = new_node ;
	count++;
	return Insert_Success ;
};

template <class list_entry>
Error_Code list<list_entry>::remove(list_entry *& xNode)
//remove the first node 
//keeps a copy to xNode
{
	if(count == 0)
		return Position_Con_Error;
	xNode = head;
	head  = head->next;
	count--;
	return Remove_Success;
}