#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <string.h>


typedef int element;
typedef struct DlistNode{
	element data;
	struct DlistNode* llink;
	struct DlistNode* rlink;
}DlistNode;

void init(DlistNode* phead)
{
	phead->llink=phead;
	phead->rlink=phead;
}

void display(DlistNode* phead)
{
	DlistNode* p;
	for(p=phead->rlink ; p!=phead ; p=p->rlink)
	{
		printf("<---| %x | %d | %x |--->\n",p->llink , p->data, p->rlink);
	}
	printf("\n");
}

void dinsert_node(DlistNode* before , DlistNode *new_node)
{
	new_node->llink = before;
	new_node->rlink = before->rlink;
	before->rlink->llink = new_node;
	before->rlink = new_node;
}
void dremove_node(DlistNode *phead_node , DlistNode* removed)
{
	if(removed == phead_node) return;
	removed->llink->rlink = removed->rlink;
	removed->rlink->llink = removed->llink;
	free(removed);
}

main()
{
	DlistNode head_node;
	DlistNode* p[10];
	int i;

	init(&head_node);
	for(i=0 ; i<5 ; i++)
	{
		p[i] = (DlistNode*)malloc(sizeof(DlistNode));
		p[i]->data = i;

		dinsert_node(&head_node,p[i]);
	}
	dremove_node(&head_node,p[4]);
	display(&head_node);
}