[C++] 突破C语言难点之单链表？一绘图即可

#include <stdio.h>#include <stdlib.h>//结构体的写法:某一种结构的单一个体struct Node{  int data;  struct Node* next;};//有表头的链表，创建表头--->创建结构体变量struct Node* createHead(){  //指针如何变成变量  struct Node* headNode = (struct Node*)malloc(sizeof(struct Node));  //使用变量有一个规则:变量使用前必须要初始化  //结构体变量  //(*headNode).data  //不做数据的初始化，因为第一个节点不存放数据  headNode->next = NULL;  return headNode;}//未插入做准备//创建节点-->把别人的数据变成节点的模样//节点模样-->结构体变量：和表头是一样的struct Node* createNode(int data){  struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));  newNode->data = data;  newNode->next = NULL;  return newNode;}//表头插入//想清楚表头插入是怎么插入，把姿势想清楚void insertByHead(struct Node* headNode,int data){  struct Node* newNode = createNode(data);  newNode->next = headNode->next;  headNode->next = newNode;}//指定位置删除void deleteByAppoin(struct Node* headNode, int posData){  struct Node* posNodeLeft = headNode;  struct Node* posNode = headNode->next;  //两个条件顺序不能改变  NULL->data 会引发冲突  //posNode!=NULL 没有找到退出循环的条件  while (posNode != NULL&&posNode->data != posData)  {  //不等于，并排往下走  /*    //第一种写法    posNodeLeft=posNodeLeft->next;    posNode=posNode->next;  */  posNodeLeft = posNode;  posNode = posNode->next;  }  //分析退出循环的条件  if (posNode == NULL)  {  printf("为找到指定位置,无法删除!\n");  return;  }  else  {  posNodeLeft->next = posNode->next;  free(posNode);  posNode = NULL;  printf("删除成功\n");  }}//查找结点struct Node* searchByData(struct Node* headNode, int posData){  struct Node* pMove = headNode->next;  while (pMove != NULL&&pMove->data != posData)  {  pMove = pMove->next;  }  return pMove;}//删除所有的相同的数据void deleteAll(struct Node* headNode, int posData){  while (searchByData(headNode, posData) != NULL)  {  deleteByAppoin(headNode, posData);  }}//打印函数封装void printList(struct Node* headNode){  struct Node* pMove = headNode->next;  //从第二个节点开始打印  while (pMove != NULL)  {  printf("%d\t", pMove->data);  pMove = pMove->next;  }  printf("\n");}//表尾插入: 找到表尾：tailNode tailNode->next=newNode;void insertByTail(struct Node* headNode, int data){  struct Node* newNode = createNode(data);  struct Node* tailNode = headNode;  while (tailNode->next != NULL)  {  tailNode = tailNode->next;  }  tailNode->next = newNode;}//表头删除void deleteByHead(struct Node* headNode){  struct Node* secondNode = headNode->next;  //确保secondNode不能为NULL，因为NULL没有next  if (secondNode != NULL)  {  headNode->next = secondNode->next;  free(secondNode);  secondNode = NULL;  }  }//表尾删除void deleteByTail(struct Node* headNode){  struct Node* tailLeftNode = NULL;  struct Node* tailNode = headNode;  while (tailNode->next != NULL) //循环条件一次都没有执行，意味着链表为NULL  {  tailLeftNode = tailNode;  tailNode = tailNode->next;  }  if (tailLeftNode == NULL)  {  printf("链表为NULL无法删除！");  return;  }  else  {  tailLeftNode->next = NULL;  //前一个结点的next指针未做处理  free(tailNode);  tailNode->next = NULL;  }}void deleteByTailWay(struct Node* headNode){  if (headNode->next == NULL)  {  return;  }  struct Node* tailNode = headNode;  while (tailNode->next->next != NULL)  {  tailNode = tailNode->next;  }  free(tailNode->next);  tailNode->next = NULL;}//指定插入void insertByAppoin(struct Node* headNode, int data, int posData){  struct Node* posNodeLeft = headNode;  struct Node* posNode = headNode->next;  //为什么不能缓过来??  //一旦posNode==NULL  那么不存在NULL->data操作  //a&&b  a=0  b不会执行  //1>3&&a=1;  while (posNode != NULL&&posNode->data != posData)  {  posNodeLeft = posNode;  posNode = posNodeLeft->next;  }  if (posNode == NULL)  {  printf("未找到指定位置无法插入!\n");  return;  }  else  {  struct Node* newNode = createNode(data);  posNodeLeft->next = newNode;  newNode->next = posNode;  printf("插入成功！\n");  }}int main(){  struct Node* list = createHead();  for (int i = 0; i < 3; i++)  {  insertByHead(list, i);  insertByHead(list, i);  }  printList(list);  deleteByAppoin(list, 1);  //只能删除第一个被找到的元素  printList(list);  deleteAll(list,2);  printList(list);  insertByTail(list, 100);  printList(list);  insertByAppoin(list, 90, 100);  printList(list);  deleteByHead(list);  printList(list);  deleteByTail(list);  printList(list);  deleteByTailWay(list);  printList(list);  system("pause");  return 0;}