链表指一种数据结构，相对于数组来说，链表存储数据时，空间不连续，具有省空间的优点。

想要操作链表，需要先掌握手动开辟空间的方法。通过malloc可以手动开辟一个堆区空间

malloc函数功能如下：

malloc, free- allocate and free dynamic memory#include <stdlib.h>void *malloc(size_t size);size_t size:指定开辟空间的大小    The  malloc()  function  allocates  size    bytes and returns a pointer to the allo‐    cated memory.  The memory  is  not  ini‐    tialized.   If  size is 0, then malloc()    returns either NULL,void *：被称为空指针类型，可以理解为万能指针，可以转换为任何数据类型，        通过强制转换       用来接收malloc开辟空间返回的首地址void free(void *ptr);

使用案例：

#include <stdio.h>#include <stdlib.h>#include <string.h>typedef struct Person{	int age;	char name[20];}Per,*pPer;int main(){	Per per;	pPer p=NULL;	p = (pPer)malloc(sizeof(Per));	scanf("%d%s", &per.age, per.name);	printf("%s\t%d\n", per.name, per.age);	scanf("%d%s", &p->age, p->name);	printf("%s\t%d\n", p->name, p->age);	system("pause");	return 0;}

单向链表操作：

1、先确定链表节点的数据结构

链表是结构体形式的数据结构

链表数据结构

typedef struct info{	char name[20];	int age;}Info,*pInfo;typedef struct Student{	Info msg;	struct Student *next;}Stu,*pStu;

2、确定使用有头还是无头链表，创建链表头

有头和无头的区别就是链表头是否用来存储数据

创建表头

pStu CreatHead(){	pStu head= (pStu)malloc(sizeof(Stu));	head->msg.age=0;	strcpy(head->msg.name," "); 	head->next=NULL;	return head;}

3、创建子节点

pStu CreateNode(Info msg){	pStu iNode=(pStu)malloc(sizeof(Stu));	iNode->msg = msg;	iNode->next = NULL;	return iNode ;}

4、将子节点插入到链表中

注意链表中的操作遵循四字法则“先连后断”

1)头插法

每次插入节点的时候都是将节点插入到头节点的后面，最终解过为逆序

void InserHead(pStu head,Info msg){	pStu NewNode=CreateNode (msg);	NewNode->next=head->next;	head ->next=NewNode;}

2)尾插法

每次插入节点的时候都是将节点插入到尾节点的后面，最终解过为顺序

void InserEnd(pStu head,Info msg){	pStu pMove=head;	pStu NewNode=CreateNode (msg);	if(head->next==NULL)		head->next = NewNode;	while(pMove->next!=NULL)	{		pMove =pMove->next;	}	pMove->next=NewNode;	NewNode->next=NULL;}

3)中间插

void InserMid(pStu head,Info msg,int number){	int i=1;	pStu pMove=head;	pStu NewNode=CreateNode (msg);	if(head->next==NULL)		head->next = NewNode;	while(i!=number)	{		i++;		pMove =pMove->next;	}	NewNode->next=pMove->next;	pMove->next=NewNode;}

4）查找

pStu SearchNode(pStu head,Info msg){	pStu pMove =head->next;	if(head->next==NULL)		printf("链表为空");	while(pMove->next!=NULL)	{		if(strcmp(pMove->msg.name,msg.name)==0)		{			return pMove;			break;		}		pMove=pMove->next;		if(pMove->next==NULL)		{			return NULL;		}	}}

5）修改

void ChangeNode(pStu head, Info msg){	pStu tmp = SearchNode(head, msg);	if (tmp == NULL)	{		printf("查无此信息\n");	}	else	{		printf("请输入修改信息：\n");		scanf("%s", tmp->msg.name);	}}

6）删除

//删除信息void  DeletehNode(pStu head, Info msg){	pStu tmp = head;	pStu pMove = head->next;	if (head->next == NULL)	{		printf("链表为空\n");	}	while (pMove->next != NULL)	{		if (strcmp(pMove->msg.name, msg.name) == 0)		{			break;		}		tmp = pMove;		pMove = pMove->next;		if (pMove == NULL)		{			printf("查无此信息\n");			return ;		}	}	tmp->next = pMove->next;	free(pMove);	printf("free success\n");}

7，遍历所有节点

//遍历所有节点void Print(pStu head){	int i = 1;	pStu pMove = head->next;	while (pMove!= NULL)	{		printf("第%d个节点内的数据:name=%s\tage=%d\n", i,pMove->msg.name, pMove->msg.age);		i++;		pMove = pMove->next;	}}