单链表的实现

头文件 SList.h

# pragma once
# include "SList.h"
# include <stdio.h>
# include <stdlib.h>
# include <assert.h>
typedef int DataType;
typedef struct SList
{
	DataType data;
	struct SList *next;
}SList, *phead, **pphead;
//头插
void SListPushFront(pphead head, DataType x);
//尾插
void SListPushBack(pphead head, DataType x);
//头删
void SListPopFront(pphead head);
//尾删
void SListPopBack(pphead head);
//任意位置插
void Insert(pphead head, phead pos, DataType x);
//任意位置删
void Erase(pphead head, phead pos); 
//算节点数
int SListSize(phead head);
//判断是否为空
int SListEmpty(phead head);
//查某个数所在节点位置
phead SListFind(phead head, DataType x);
//删除第一个x
void SlistRemove(pphead head, DataType x);
//删除x
void SlistRemoveAll(pphead head, DataType x);
//销毁
void SListDestory(pphead head);
//打印
void Show(SList *head);
//测试
void SListTest();

SList.c 文件

# include "SList.h" 
//生成一个新的结点 
static SList* BuyNewNode(DataType data)
{ 	SList *node = (SList*)malloc(sizeof(SList)); 	
	node->data = data; 	
	node->next=NULL; 	
	return node; 
} 
void SListPushFront(pphead head, DataType x)//头插
{
	if (*head == NULL)
		*head = BuyNewNode(x);
	else
	{
		phead node = BuyNewNode(x);
		node->next = *head;
		*head = node;
	}
}
void SListPushBack(pphead head, DataType x)//尾插
{
	if (*head == NULL)
		*head = BuyNewNode(x);
	else
	{
		phead node = *head;
		while (node->next != NULL)
			node = node->next;
		node->next = BuyNewNode(x);
	}
}
void SListPopFront(pphead head)//头删
{
	if (*head == NULL)//链表为空链表
	{
		printf("链表为空\n");
		return;
	}
	phead node = (*head)->next;
	free(*head);
	*head = node;
}
void SListPopBack(pphead head)//尾删
{
	phead node = *head;
	phead newnode;
	if (*head == NULL)//链表为空链表
	{
		printf("链表为空\n");
		return;
	}
	if ((*head)->next == NULL)//链表只有一个节点
	{
		free(*head);
		*head = NULL;
	}
	while (node->next->next)//找到倒数第二个，删掉倒数第一个
		node = node->next;
	newnode = node->next;//倒数第一个
	node->next = newnode->next;//最后一个NULL赋给倒数第二个
	free(newnode);//释放倒数第一个
}

void SListInsert(pphead head, phead pos, DataType x)//任意位置插
{
	phead node = *head;
	phead newnode = BuyNewNode(x);
	if (*head == pos)
		SListPushFront(head, x);
	while (node->next != pos)
		node = node->next;
	newnode->next = pos;
	node->next = newnode;
}
void SListErase(pphead head, phead pos)//任意位置删
{

	phead node = *head;
	if (*head == pos)
	{
		SListPopFront(head);
		return;
	}
	while (node->next != pos)
		node = node->next;
	node->next = pos->next;
	free(pos);
}
int SListSize(phead head)//算节点数
{
	size_t size = 0;
	phead node = head;
	while (node)
	{
		node = node->next;
		size++;
	}
	return size;
}
int SListEmpty(phead head)//判断是否为空
{
	return head == NULL ? 1 : 0;
}
phead SListFind(phead head, DataType x)//查某个数所在节点位置
{
	phead node = head;
	while (node)
	{
		if (node->data == x)
			return node;
		node = node->next;
	}
	return NULL;
}
void SlistRemove(pphead head, DataType x)//删除第一个x
{
	phead pos = SListFind(*head, x);
	if (head == NULL)
		return;
	if (*head == NULL)
		return;
	if (pos != NULL)
		SListErase(head, pos);
}
void SlistRemoveAll(pphead head, DataType x)//删除x
{
	phead node = *head;
	while (node->next)
	{
		if (node->next->data == x)
		{
			phead newnode = node->next;
			node->next = newnode->next;
			free(newnode);
		}
		else
			node = node->next;
	}
	if ((*head)->data == x)
		SListPopFront(head);
}
void SListDestory(pphead head)//销毁
{
	phead node = *head;
	while (node)
	{
		phead newnode = node->next;
		free(node);
		node = newnode;
	}
	*head = NULL;
}
//显示
void Show(phead head)
{
	
	SList *phead = head;
	for (; phead!= NULL; phead = phead->next)
	{
		printf("%2d ->", head->data);
	}
	printf("NULL\n");
}
//测试
void SListTest()
{
	SList *head = NULL;
	SListPushFront(&head, 1);
	SListPushFront(&head, 2);
	SListPushBack(&head, 2);
	printf("%d\n", SListSize(head));
	Show(head);
}

测试文件 test.c

# include "SList.h"

int main()
{
	SListTest();
	system("pause");
	return 0;
}