简单的单链表链表实现 不足之处请留言指出。

以下是头文件：

#pragma once
#ifndef __LIST_H__
#define __LIST_H__

#define _CRT_SECURE_NO_WARNINGS

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


#endif

以下是代码实现：

#include "list.h"

typedef int ElemType;
typedef struct node{      //节点
	ElemType elem;		
	struct node* next;		
}node,*pNode;

typedef struct {       //链表
	pNode head, tail;    //头、尾、指向下一个的节点指针
	int len;			  //长度
}LinkList,*PlinkList;
enum { ERROR, OK };    //0  1

PlinkList initList();     //申请头节点
int clearList(LinkList* L);   //清空
int destroyLIst(LinkList* L);  //销毁
int insFirst(LinkList* L, ElemType e);    //头插
int insEnd(LinkList* L, ElemType e);    //尾插
int insDelete(LinkList* L);    //头删
int locateElem(const LinkList* L, ElemType e);   //查询e出现的第一个位置
int deleteELem(LinkList* L, ElemType e);    //删除第一个出现的e
int isEmpty(const LinkList* L);   //判空
void printList(const LinkList* L);	//打印
int lenList(const LinkList* L);   //长度

void test4();


//int main()
//{	
//	printf("------------------单链表测试------------------\n");
//	test4();
//
//	int i = 43;
//	printf("%d\n", printf("%d", printf("%d", i)));
//
//	system("pause");
//	return 0;
//}

void test4()
{
	PlinkList list = initList();

	printf("%d\n", list->head->elem);
	printf("%p\n", list->head->next);
	printf("%p\n", list->head);
	printf("%p\n", list->tail);
	printf("%p\n", list->tail->next);
	printf("%p\n", list);

	printf("%d\n", isEmpty(list));

	insFirst(list, 1); insFirst(list, 2); insFirst(list, 3);
	insEnd(list, 1); insEnd(list, 222); insEnd(list, 222);
	printList(list);

	deleteELem(list, 222);
	printList(list);

	printf("%d\n", locateElem(list, 222));

	insDelete(list);
	printList(list);

	printf("len:%d\n", lenList(list));

	clearList(list);
	printList(list);

	printf("%d\n", destroyLIst(list));

}

PlinkList initList()     //申请头节点
{
	LinkList* L;
	L = (PlinkList)malloc(sizeof(LinkList));
	L->head = (node*)malloc(sizeof(node));
	L->tail = (node*)malloc(sizeof(node));
	L->head->next = NULL;
	L->tail->next = NULL;
	L->head->elem = 0;
	L->tail->elem = 0;
	L->len = 0;
	return L;
}

int clearList(LinkList* L)
{
	assert(L);
	pNode temp = NULL;
	pNode p = L->head->next;
	while (p != NULL)
	{
		temp = p->next;
		free(p);
		p = temp;
	}
	L->head->next = NULL;
	L->tail->next = NULL;
	L->len = 0;
	return OK;
}

int destroyLIst(LinkList* L)
{
	assert(L);
	//删除链表L中除了头节点之外的所有节点
	clearList(L);
	free(L);
	L = NULL;
	return OK;
}

int insFirst(LinkList* L, ElemType e)    //头插
{
	assert(L);
	pNode temp = (pNode)malloc(sizeof(node));
	temp->elem = e;
	if (L->head->next == NULL)
	{
		L->tail = temp;
	}
	temp->next = L->head->next;
	L->head->next = temp;
	L->len++;
	return OK;
}

int insEnd(LinkList* L, ElemType e)    //尾插
{
	assert(L);
	pNode temp = (pNode)malloc(sizeof(node));
	temp->elem = e;
	if (L->head->next == NULL)
	{
		L->head = temp;
	}
	L->tail->next = temp;
	temp->next = NULL;
	L->tail = temp;
	L->len++;
	return OK;

}

int insDelete(LinkList* L)    //头删
{
	assert(L);
	pNode temp = L->head->next->next;
	free(L->head->next);
	L->head->next = temp;
	L->len--;
	return OK;
}

int locateElem(const LinkList* L, ElemType e)
{
	assert(L);
	int i = 0;
	pNode p = L->head->next;
	while (p != NULL)
	{
		++i;
		if (p->elem == e)
		{
			return i;
		}
		p = p->next;
	}
	return ERROR;
}

int deleteELem(LinkList* L, ElemType e)    //删除第一个出现的e
{
	assert(L);
	pNode p = L->head->next;
	pNode temp = L->head;     //记录p的前驱
	while (p != NULL)
	{
		if (p->elem == e)
		{
			temp->next = p->next;
			free(p);
			L->len--;
			return OK;
		}
		p = p->next;
		temp = temp->next;
	}
	return ERROR;
}

int isEmpty(const LinkList* L)
{
	assert(L);
	if (L->head->next == L->tail->next)
	{
		return 1;
	}
	return 0;
}

void printList(const LinkList* L)
{
	assert(L);
	pNode p = L->head->next;
	while (p != NULL)
	{
		printf("%d ", p->elem);
		p = p->next;
	}
	printf("\n");
}

int lenList(const LinkList* L)
{
	assert(L);
	return L->len;
}