一文带你搞懂单链表

1、不带头节点的单链表
2、带头节点的单链表
3、不带头结点的双链表
4、带头结点的双链表
5、带头结点的双向循环链表

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

typedef struct node
{
 int data; //"数据域" 保存数据元素
 struct node * next; //保存下一个数据元素的地址
}Node;

void printList(Node *head){
    Node *p = head;
    while(p != NULL){
        printf("%d\n",p->data);
        p = p -> next;
    }
}

int main(){
  
  Node * a = (Node *)malloc(sizeof(Node));
  Node * b = (Node *)malloc(sizeof(Node));
  Node * c = (Node *)malloc(sizeof(Node));
  Node * d = (Node *)malloc(sizeof(Node));
  Node * e = (Node *)malloc(sizeof(Node));
  
  a->data = 1;
  a->next = b;
  
  b->data = 2;
  b->next = c;
  
  c->data = 3;
  c->next = d;
  
  d->data = 4;
  d->next = e;
  
  e->data = 5;
  e->next = NULL;
  
  printList(a);
}

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

typedef struct node
{
 int data; //"数据域" 保存数据元素
 struct node * next; //保存下一个数据元素的地址
}Node;

//创建链表，即创建表头指针 
Node* creatList()
{
 Node * HeadNode = (Node *)malloc(sizeof(Node));
 //初始化
 HeadNode->next = NULL;
 return HeadNode;
}

//创建节点 
Node* creatNode(int data)
{
 Node* newNode = (Node *)malloc(sizeof(Node));
 //初始化
 newNode->data = data;
 newNode->next = NULL;
 return newNode;
}

//遍历链表
void printList(Node *headNode){
    Node *p = headNode -> next;
    while(p != NULL){
        printf("%d\t",p->data);
        p = p -> next;
    }
    printf("\n");
}

//插入节点：头插法
void insertNodebyHead(Node *headNode,int data){
 //创建插入的节点 
    Node *newnode = creatNode(data);

    newnode -> next = headNode -> next;
    headNode -> next = newnode;
}

//删除节点
void deleteNodebyAppoin(Node *headNode,int posData){
 // posNode 想要删除的节点，从第一个节点开始遍历 
 // posNodeFront 想要删除节点的前一个节点 
    Node *posNode = headNode -> next;
    Node *posNodeFront = headNode;
    
 if(posNode == NULL)
  printf("链表为空，无法删除");
 else{
  while(posNode->data != posData)
  {
   //两个都往后移，跟着 posNodeFront 走 
   posNodeFront = posNode;  
   posNode = posNodeFront->next;
   if (posNode == NULL)
   {
    printf("没有找到，无法删除");
    return; 
   }
  }
  //找到后开始删除 
  posNodeFront->next = posNode->next;
  free(posNode);
 } 
}

int main(){
 
 Node* List = creatList();
 
 insertNodebyHead(List,1); 
 insertNodebyHead(List,2); 
 insertNodebyHead(List,3);  
 printList(List);
 
 deleteNodebyAppoin(List,2);
 printList(List);
 
 return 0;
}