#include<bits/stdc++.h>

#define ElemType int 
#define Status int

#define INIt_SIZE 100

#define OK 1;
#define ERROR 0;

using namespace std;

typedef struct lnode{
	ElemType data;
	struct lnode *next;
}lnode,*linklist;//*linklistΪָÏòlnodeÀàÐ͵ÄÖ¸Õ룬¶¨ÒåÁ´±íÍ·Ö¸Õë
//linklist ÒѾ­´ú±íÖ»Ö¸ÕëÁË¡£

Status initlist(linklist &L){
	L = (lnode *)malloc(sizeof(lnode));
	if(L == NULL) 
	{
		printf("´æ´¢·ÖÅäʧ°Ü£¡\n");
		return ERROR;		
	}
	L->next = NULL;
	return OK;
} 
/*
µ¥Á´±íµÄ´´½¨£¬´Ë´¦Îªtail²å·¨ 
*/
Status createlist(linklist &L)
{
	if(L == NULL) //
		initlist(L);
	linklist p,tial;
	tial = L;		
	
	printf("ÇëÊäÈëÏëÒª´´½¨Á´±íµÄ³¤¶È(ĬÈϳ¤¶ÈΪ5)£º\n");
	//scanf("%d",&n); 
	int n = 5;
	int a[]={0,1,2,3,4,5};
	for(int i = 1;i <=n; ++i)
	{
		p = (linklist) malloc(sizeof(lnode));
		//scanf("%d",&(p->data));//´Ë´¦Ä¬ÈÏElemTypeΪintÐÍ
		p->data = a[i];
		p->next = NULL;
		tial->next = p; //²åÈëµ½±íÍ·¡£
		tial = p;	//β½áµãÖ¸Ïòд´½¨µÄ½áµã£» 		  
	}
	return OK;
}

Status emptylist(linklist L)
{
	if(L->next == NULL)
	{
		printf("This linked list is empty\n");
		return OK;
	}
	else
	{
		printf("This linked list not is empty\n");
		return ERROR;
	}
}

int getlength(linklist L)
{
	linklist p = L->next;
	int length = 0;
	while(p) {
		p = p->next;
		++length;
	}
	return length;
}

/*
insert e at i-th position ;
*/
Status insert(linklist &L,int i,ElemType e)
{
	linklist p = L;
	int it = 0;//
	while(p && it < i-1) //ÕÒµ½iµÄÇ°Ò»¸ö½áµã Õý³£Í˳öʱpÖ¸Ïòi-1 
	{
		p = p->next;
		++it;		
	}
	if(!p || it > i-1)//ͬʱÅжÏiÖµÊÇ·ñºÏ·¨£¬it > i-1 ¼´i <= 0   
		return ERROR;
	linklist nd = (linklist) malloc(sizeof(lnode));
	nd->data = e;
	nd->next = p->next;
	p->next = nd;  
	return OK;
}

/*
½«Á´±íÖû»Îª¿Õ±í
±£ÁôÍ·½áµã 
*/
Status clearlist(linklist &L)
{
	if(emptylist(L)) 
		return ERROR;

	linklist p = L->next,s;
	while(p) 
	{
		s = p->next;
		free(p);
		p = s;		
	}
	L->next = NULL;//ÈÝÒ×Íü¼Ç 
	 
	return OK; 
}

/*
´Ý»ÙÁ´±í 
*/
Status destorylist(linklist &L)
{
	if(!emptylist(L)) 
		clearlist(L);
	free(L);		
	return OK;
}

/*
ɾ³ýÖ¸¶¨Î»ÖÃÔªËØ£¬²¢½«¸ÃÔªËØÖµ¸³¸øe´ø»Ø¡£ 
*/ 
Status deletelist(linklist &L,int i,ElemType e)
{
	if(i < 1 || i > getlength(L)) 
		return ERROR;
	
	linklist p = L;
	int it = 0;	
	while(p && it < i-1)
	{
		p = p->next;
		++it;
	}
	if(!p || it > i-1) return ERROR;
	
	linklist s = p->next;
	//p->next = (p->next)->next;
	p->next = s->next;
	free(s);//ÊÍ·Å¿Õ¼ä 
}


/*

*/
Status getelem(linklist L,int i,ElemType &e)
{
	linklist p = L;//L±È½ÏºÃ Èç¹ûLÊÇ¿Õ 
	int it = 0;    //J count number;
	while(p && it < i){
		p = p->next;
		++it;
	}
	if(!p || it > i)//i==0 !p==1 
		return ERROR;
	
	e = p->data;
	return OK;			
}

Status printlist(linklist L)
{
	int length = getlength(L);
	linklist p = L->next;
	printf("Á´±íÄÚÔªËØΪ£º");
	for(int i = 1;i <= length; ++i)
	{
		printf("%d ",p->data);
		p = p->next;		
	}
	printf("\n");
}

/*
i ´ú±íλÐò  
*/
Status priorelem(linklist L,int i,int &e){
	
	linklist p = L;
	int cnt = 0;
	while(p && cnt < i-1)
	{
		p = p->next;
		++cnt;
	}
	if(i <= 1 || !p) return ERROR;
	
	e = p->data;
	return OK;
}

/*
Á´±í×îºóÒ»¸ö½áµãûÓÐÖ±½Óºó¼Ì 
Ö±½ÓÅпռ´¿É 
*/
nextelem(linklist L,int i,int &e)
{
	linklist p = L;
	int cnt = 0;
	
	while(p && cnt < i +1) //  i 1 -n-1
	{
		p = p->next;
		++cnt;
	}	
	if(!p || i < 1) return ERROR;
	e = p->data;
	return OK;
}

int main()
{
	linklist L ;
	if(initlist(L)) 
		printf("Á´±í´´½¨³É¹¦£¡\n");
	else 
		printf("Á´±í´´½¨Ê§°Ü!\n");
		 
	emptylist(L); 
	printf("Ä¿Ç°Á´±íµÄ³¤¶ÈΪ %d\n",getlength(L));
	
	createlist(L);
	
	printlist(L);	
	
	int e = 6;
	insert(L,5,e);
	
	printf("insert length = %d\n",getlength(L));
	printlist(L);	
	emptylist(L);
	
	deletelist(L,2,e);
	printf("delete length = %d\n",getlength(L));
	printlist(L);
	

	int pe1=-1000,pe2=-1000;
	priorelem(L,2,pe1);
	priorelem(L,5,pe2);
	printf("Prior of 2-th =%d  Prior of 5-th =%d \n",pe1,pe2);
	
	int ne1=-1000,ne2=-1000;
	nextelem(L,1,ne1);
	nextelem(L,4,ne2);
	printf("next of 1-th=%d  next of 4-th=%d \n",ne1,ne2);
	
	clearlist(L);
	emptylist(L);
	printf("clear  length=%d\n",getlength(L)); 
	
	destorylist(L); 
	
	return 0;
}