不带头结点的单链表常用操作（一）

struct Node* head = NULL;//头节点定义为全局变量，便于操作
struct Node//节点
{
	int data;
	struct Node* next;
}; 
struct Node* CreatList()
{
	int n;//数据个数
	printf("请输入要存储数据的个数：n");
	scanf("%d",&n);
	int i=1;
	struct Node* node=(struct Node*)malloc(sizeof(struct Node));//为第一个节点开辟空间
    head =node;
	printf("请输入数据n");
	while (i < n)
	{
		scanf("%d", &node->data);
		node->next= (struct Node*)malloc(sizeof(struct Node));//为后续节点开辟空间
		node = node->next;
		i++;
	}
	scanf("%d", &node->data);//输入尾结点数据
	node->next= NULL;
	return head;
}

struct Node* Hinsert()//头插
{
	int data;
	printf("请输入要头插的数据：n");
	scanf("%d", &data);
	struct Node* node=(struct Node*)malloc(sizeof(struct Node));
	node->data = data;
	if (head == NULL)//若表为空，插入节点即为头节点
	{ 
		head = node;
		return head;
	}
	node->next = head;//原头节点为插入节点的后继节点
	head = node;//插入节点成为新的头节点
	return head;
}

struct Node* Tinsert()
{
	int data;
	printf("请输入要尾插的数据：n");
	scanf("%d", &data);
	struct Node* node= (struct Node*)malloc(sizeof(struct Node));
	node->data = data;
	if (head == NULL)//若链表为空，插入节点即为头节点
	{
		head = node;
		return head;
	}
	struct Node* p = head;
	while (p->next)
	{
		p = p->next;
	}
	p->next = node;//找到尾结点后将要插入的节点连接
	node->next = NULL;
	return head;
}

struct Node* InverseList1()//反转指针实现反转链表
{
	if (head == NULL)
		return NULL;
	struct Node* p1 = NULL;//这里需要定义三个指针
	struct Node* p2 =head ;//反转操作通过p1,p2实现
	struct Node* p3 = head->next;//定义p3是为了让三个指针逐个后移，从而反转每个指针
	while (p2)//p2为空后操作完成
	{
		p2->next= p1;//指针反向
		p1= p2;//p1后移
		p2 = p3;//p2后移
		if(p3)
		p3 = p3->next;//p3后移
	}
	head = p1;//反转后的头节点为p1
	return head;
}

反转操作是由p1,p2完成

struct Node* InverseList2() //头插法实现反转链表
{
	if (head == NULL)
	{
		return NULL;
	}
	struct Node* node = head;//为了保持头节点不变
	struct Node* head2 = NULL;//第二个链表头
	while (node)
	{
		struct Node* node3 = node->next;//记录node的下一个位置，以便顺利完成原链表节点后移
		node->next=head2;//节点插入,node.next已改变因此需要上一步的node3来记录原本的node.next
		head2 = node;//插入节点成为新头结点
		node = node3;//原链表节点后移
	}
	head = head2;
	return head;
}

功能展示：

完整代码：

#define _CRT_SECURE_NO_WARNINGS 1
#include
#include 
struct Node* head = NULL;
struct Node
{
	int data;
	struct Node* next;
}; 
struct Node* Hinsert()//头插
{
	int data;
	printf("请输入要头插的数据：n");
	scanf("%d", &data);
	struct Node* node=(struct Node*)malloc(sizeof(struct Node));
	node->data = data;
	if (head == NULL)
	{ 
		head = node;
		return head;
	}
	node->next = head;
	head = node;
	return head;
	
}
struct Node* Tinsert()
{
	int data;
	printf("请输入要尾插的数据：n");
	scanf("%d", &data);
	struct Node* node= (struct Node*)malloc(sizeof(struct Node));
	node->data = data;
	if (head == NULL)
	{
		head = node;
		return head;
	}
	struct Node* p = head;
	while (p->next)
	{
		p = p->next;
	}
	p->next = node;
	node->next = NULL;
	return head;
}
struct Node* CreatList()
{
	int n;
	printf("请输入要存储数据的个数：n");
	scanf("%d",&n);
	int i=1;
	struct Node* node=(struct Node*)malloc(sizeof(struct Node));
    head =node;
	printf("请输入数据n");
	while (i < n)
	{
		scanf("%d", &node->data);
		node->next= (struct Node*)malloc(sizeof(struct Node));
		node = node->next;
		i++;
	}
	scanf("%d", &node->data);
	node->next= NULL;
	return head;
}
void ShowList()
{
	if (head == NULL)
	{
		printf("链表为空n");
	}
	struct Node* node = head;
	while (node)
	{
		printf("%d ",node->data);
		node = node->next;
	}
	printf("n");
}
struct Node* InverseList1()//反转指针实现反转链表
{
	if (head == NULL)
		return NULL;
	struct Node* p1 = NULL;
	struct Node* p2 =head ;
	struct Node* p3 = head->next;
	while (p2)
	{
		p2->next= p1;
		p1= p2;
		p2 = p3;
		if(p3)
		p3 = p3->next;
	}
	head = p1;
	return head;
}
struct Node* InverseList2() //头插法实现反转链表
{
	if (head == NULL)
	{
		return NULL;
	}
	struct Node* node = head;
	struct Node* head2 = NULL;
	while (node)
	{
		struct Node* node3 = node->next;
		node->next=head2;
		head2 = node;
		node = node3;
	}
	head = head2;
	return head;
}
int main() 
{
	struct Node* head=NULL;
	head=CreatList();
	head=InverseList2();
	printf("反转后：n");
	ShowList();
	head=InverseList1();
	printf("反转后：n");
	ShowList();
	head=Tinsert();
	printf("尾插后：n");
	ShowList();
	head = Hinsert();
	printf("头插后：n");
	ShowList();
	return 0;
}

 一些感想：完成这些操作，真的能加深对指针的理解，同时能增强对指针的掌控能力。