链表

#include <iostream>
using namespace std;
struct stnode     //stnode为结构体名字
{   
 //数据部分
 int value;
 //指针部分
 stnode* pNext;//结构体类型的指针
};

stnode* g_phead = NULL; //链表头结点
//添加一个节点                                                从头部添加
void addnode(stnode** pphead, stnode* paddnode)
{
 if (pphead == NULL)
 {
  return;
 }
 stnode* phead = *pphead;//一个指针 指向头结点的指针
 if (phead == NULL)
 {
  //说明链表头为NULL,无结点
  *pphead = paddnode;
  return;
 }
 paddnode->pNext = phead;
 *pphead = paddnode;
}
//插入一个节点
void InsertNode(stnode** ppHead,stnode* insertnode,stnode* node)
{
 if (node==NULL||insertnode==NULL)
 {
  return;
 }
 insertnode->pNext = node->pNext;
 node->pNext = insertnode;
}
//删除某一个节点
void deletenote(stnode** ppHead, int value)
{
 if (ppHead == NULL || *ppHead == NULL)
 {
  return;
 }
 stnode*pCur = *ppHead;
 if (pCur->value == value)
 {
  //头结点
  stnode* pDeleteNode = pCur;
  *ppHead = pCur->pNext;
  delete pDeleteNode;
  return;
 }
 while (pCur)
 {
  if (pCur->pNext != NULL && pCur->pNext->value == value)
  {
   //找到了，pCur为要删除结点的前一个结点
   stnode* pDelNode = pCur->pNext;
   pCur->pNext = pCur->pNext->pNext;
   delete pDelNode;
   return;

  }
  pCur = pCur->pNext;
 }

}

//查找一个节点
stnode* FindNode(stnode*pHead, int value)
{

 while (pHead)
 {
  if (pHead->value == value)
  {
   return pHead;
  }
  pHead = pHead->pNext;
 }
 return NULL;

}
//修改结点值
void AlterNode(stnode* pHead, int changeValue, int changeToValue)
{
 stnode* node = FindNode(pHead, changeValue);
 if (node == NULL)
 {
  return;
 }
 node->value = changeToValue;

}
int main()
{
 stnode* pNodel = new stnode;
 pNodel->value = 1;
 pNodel->pNext = NULL;
 stnode* pNode2 = new stnode;
 pNode2->value = 2;
 pNode2->pNext = NULL;
 stnode* pNode3 = new  stnode;
 pNode3->value = 3;
 pNode3->pNext = NULL;
 addnode(&g_phead, pNodel);
 addnode(&g_phead,pNode2);
 addnode(&g_phead,pNode3);

}