#include <iostream>

// 带头结点单链表.cpp : Defines the entry point for the console application.
//
using namespace std;

#include<stdlib.h>
typedef struct node {
	int data;
	struct node* link;
}LinkLnode, * LinkList;
void initlist(LinkList& first)
{
	first = new LinkLnode;
	first->link = NULL;
}
void clearlist(LinkList& first)//清空单链表，只保留头结点
{
	LinkList q;
	while (first->link != NULL)
	{
		q = first->link;
		first->link = q->link;//从链上摘取该节点，first->link存放后面节点的地址
		free(q);
	}
}
int length(LinkList first)
{
	LinkList p= first->link; int k = 0;
	while (p)
	{
		k++;
		p = p->link;
	}
	return k;
}
LinkList locate(LinkList& first, int i)
{
	if (i < 0)return NULL;
	LinkList p = first; int k = 0;
	while (p && k < i)
	{
		p = p->link;
		k++;
	}
	return p;
}
int insert(LinkList& first, int i,int x)
{
	LinkList p = locate(first,i-1);
	if (p == NULL)
	{
		cout << "insert,,,,p=NULL时i=" << i << endl;
		return 0;
	}
		LinkList s = new LinkLnode;
		s->data = x;
		s->link = p->link;
		p->link = s;
		return 1;
	
}
int remove(LinkList& first, int i, int x)
{
	LinkList p = locate(first,i-1);
	if(p==NULL)
	{
		cout << "remove,,,,p=NULL时i=" << i << endl;
		return 0;
	}
	if (p->link == NULL)
	{
		cout << "remove,,,,p->link==NULL时i=" << i << endl;
		return 0;
	}
	LinkList q = p->link;
	p->link = q->link;
	x = p->data;
	free(q);
	return 1;
		
}
int print(LinkList first)
{
	LinkList p = first->link; 
	while (p)
	{
		cout << p->data << endl;
		p = p->link;
	}
	return 0;
}
void printlist(LinkList first)
{
	if (first == NULL)
		return;
	printf("%d  ",first->data);
	printlist(first->link);
}
void printlistfanxiang(LinkList first)//反向输出
{
	if (first == NULL)
		return;
	
	printlist(first->link);
	printf("%d  ", first->data);
}
void listdelete(LinkList& l, int i)
{
	LinkList p = l; int j =