链表的基本操作之_增删改查

<span style="font-size:32px;"><strong style="background-color: rgb(51, 255, 51);">链表的基本操作之_增删改查</strong></span>

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

typedef struct Node
{
	int data;
	struct Node *next;

}SLIST;

SLIST *Creat_SList();
int SList_Print(SLIST *pHead);
//在节点数值为x的前面插入y
int SList_NodeInsert(SLIST *pHead,int x,int y);
//删除节点为y的链表节点。
int SList_NodeDel(SLIST *pHead,int y);
//销毁链表
int SList_Destory(SLIST *pHead);

SLIST *Creat_SList()
{
	//1.创建头结点并初始化
	SLIST *pHead =NULL;

	SLIST *pM=NULL;//辅助指针变量
	SLIST *pCur;//指向最后一个节点位置的指针

	int data=0;
	pHead=(SLIST*)malloc(sizeof(SLIST));
	pHead->data=0;
	pHead->next=NULL;

//2循环创建结点，结点数据域中的数值从键盘输入
//以-1作为输入结束标志
	printf("please input the data of node(-1 quit)");
	scanf("%d",&data);

//准备环境 让pCur指向pHead
	pCur=pHead;//一开始链表的开始也是链表的结尾；
	while (data!=-1)
	{
		//不断的malloc新节点，并且数据域赋值
		pM=(SLIST*)malloc(sizeof(SLIST));
		pM->data=data;
		pM->next=NULL;
		//不断地新节点进入链表

		//1.新节点入链表
		pCur->next=pM;
		//2.当前节点下移，（新节点变成当前节点）
		pCur=pCur->next;
		
		//如果合法，让用户再次输入需要插入的节点。
		printf("please input the data of node(-1 quit)");
		scanf("%d",&data);
	}

	return pHead;//一定要返回，不然在以后的输出，增删查改等操作就无法利用。
}

<img src="https://img-blog.youkuaiyun.com/20150420192944110?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvdTAxMjk4OTUzNg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

//链表的打印：

int SList_Print(SLIST *pHead)
{
	SLIST *p=NULL;//辅助指针，让它移动，依次输出。

	if(pHead==NULL)
	{
		return -1;
	}

	//准备环境
	p=pHead->next;
	printf("\nBegin");
	while(p)
	{
		printf("%d",p->data);
		p=p->next;
	}
	printf("End");
	return 0;
}


//销毁链表

int SList_Destory(SLIST *pHead)
{
	//删除当前节点前，需要把后继节点位置缓存
	SLIST *pTem=NULL;
	SLIST *pCur=pHead;
	if(pHead==NULL)
	{
		return -1;
	}

	while(pCur)
	{
		//缓存后继节点位置
		pTem=pCur->next;
		//删除当前节点
		free(pCur);
		//当前节点下移
		pCur=pTem;
	}
	return 0;
}

<img src="https://img-blog.youkuaiyun.com/20150420193014499?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvdTAxMjk4OTUzNg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

int SList_NodeInsert(SLIST *pHead,int x,int y)//在节点数值为x的前面插入y
{
	SLIST *pCur = NULL,*pPre=NULL,*pM=NULL;
	if(pHead==NULL)
	{
		return -1;
	}

	//环境准备；
	pPre=pHead;
	pCur=pHead->next;
	//不断的malloc新节点，并且数据域赋值
	pM=(SLIST *)malloc(sizeof(SLIST));
	pM->data=y;//????
	pM->next=NULL;
	while(pCur)
	{
		if(pCur->data==x)
		{
			break;
		}
		//让pPre下移
		pPre=pCur;//两个节点同时下移
		//让当前节点下移
		pCur=pCur->next;
	}

	//让新节点链接后继节点
	pM->next=pPre->next;
	//让前驱节点连接pM
	pPre->next=pM;
	return 0;
}

<img src="https://img-blog.youkuaiyun.com/20150420192920984?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvdTAxMjk4OTUzNg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

//删除结点为y的链表结点
int SList_NodeDel(SLIST *pHead, int y)
{
	SLIST *pCur = NULL, *pPre = NULL;
	if (pHead == NULL)
	{
		return -1;
	}
	//环境准备
	pPre = pHead;
	pCur = pHead->next;

	while(pCur)
	{
		if (pCur->data == y)
		{
			break;
		}
		//让pPre下移
		pPre = pCur;
		//让当前节点下移
		pCur = pCur->next;
	}
	if (pCur == NULL)
	{
		printf("没有找到节点 y:%d", y);
		return -2;
	}
	//执行操作
	pPre->next = pCur->next;//让指针的指向越过将要删除的节点。
	free(pCur);
	return 0;
}

<img src="https://img-blog.youkuaiyun.com/20150420193118475?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvdTAxMjk4OTUzNg==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

int main()
{
	int ret = 0;
	SLIST *pHead = NULL;
	//创建 并打印 
	pHead = Creat_SList();
	ret = SList_Print(pHead);

	//插入操作
	ret = SList_NodeInsert(pHead, 20, 19);
	ret = SList_Print(pHead);

	ret = SList_NodeDel(pHead, 19);
	ret = SList_Print(pHead);

	ret = SList_Destory(pHead);

	return 0;
}