不带头结点的节点因为插入删除的时候会改变或者删除第一个节点，所以要引入二级指针进行一系列的操作

---

头文件

#pragma once
//不带头结点的单链表
typedef struct Node
{int data;//数据Node * next;//存放下一个元素的地址
}Node;
//初始化
void InitList(Node **ps);
//头插
bool Insert_Head(Node **ps,int val);
//尾插
bool Insert_Tail(Node **ps,int val);
//按位置插入
bool Insert_Pos(Node **ps,int pos,int val);
//删除某个节点
bool Delete_Node(Node **ps,int key);
//删除整个链表
bool Delete_List(Node **ps);
//查找
Node *Search(Node *ps,int key);
//链表长度
int GetLength(Node *ps);
//打印链表的值
void Show(Node* ps);

---

cpp文件

#include<iostream>
#include<assert.h>
#include"NoList.h"
using namespace std;void InitList(Node* *ps)
{assert(ps != NULL);*ps = NULL;
}static Node* BuyNode(int val)
{Node *pnewnode = new Node();pnewnode->data = val;pnewnode->next = NULL;return pnewnode;
}
bool Insert_Head(Node* *ps,int val)
{assert(ps != NULL);Node* pnewnode = BuyNode(val);pnewnode->next = *ps;*ps = pnewnode;return true;
}bool Insert_Tail(Node* *ps,int val)
{assert(ps != NULL);Node* pnewnode = BuyNode(val);Node* pTail = *ps;if(pTail == NULL){*ps = pnewnode;//}else{	while(pTail->next != NULL){pTail = pTail->next;}pTail->next = pnewnode;}return true;
}bool Insert_Pos(Node* *ps,int pos,int val)
{assert(ps != NULL);Node * q = *ps;for(int i = 0;i<pos;i++){q = q->next;}Node *p =BuyNode(val);p->next = q->next;q->next = p;return true;
}bool Delete_Node(Node* *ps,int key)
{assert(ps != NULL);Node* p = Search(*ps,key);if(p == NULL){return false;}//删除的节点是第一个节点也是最后一个节点if(p == *ps){delete p;p = NULL;/ps = NULL;/}//删除的节点不是尾结点else if(p->next != NULL){Node * q = p->next;p->data = q->data;p->next = q->next;delete q;q = NULL;}//节点有很多，删除的节点是尾结点else if(p ->next == NULL){Node* q = *ps;for(;q->next!= NULL;q = q->next);/*q ->next = NULL;q->next ->data = NULL;delete (q->next);*/q ->next = NULL;delete (q->next);p = NULL;}return true;
}bool Delete_List(Node* *ps)
{assert(ps != NULL);Node* p;//Node* q = p;while(*ps != NULL){p = *ps;*ps = p->next;delete p;}return true;
}Node* Search(Node* ps,int key)
{assert(ps != NULL);Node * q  = ps;while(q != NULL){if(key == q->data){return q;}q = q->next;}return NULL;
}int GetLength(Node *ps)
{assert(ps != NULL);int length = 0;for(Node* q = ps;q!= NULL;q = q->next){length++;}return length;
}void Show(Node* ps)
{for(Node *q = ps;q!= NULL;q= q->next){cout << q->data << " " ;}cout <<endl;
}

---

主函数

#include<iostream>
#include<assert.h>
#include"NoList.h"
using namespace std;int main()
{Node* head;InitList(&head);/*for(int i = 0;i<10;i++){Insert_Head(&head,i);}*/for(int i = 0;i<10;i++){Insert_Tail(&head,i,i);}Show(*&head);cout << GetLength(head) << endl;Insert_Pos(&head,5,111);Show(*&head);cout << GetLength(head) << endl;Delete_Node(&head,5);Show(head);cout << GetLength(head) << endl;Delete_List(&head);Show(head);return 0;
}