#ifndef _CIRCLELIST_H_

 #define _CIRCLELIST_H_

 typedef void CircleList;

 //

 typedef struct _tag_CircleListNode

 {

     struct _tag_CircleListNode* next;

 }CircleListNode;

 //创建一个循环链表

 CircleList* CircleList_Create();

 //删除一个循环链表

 void CircleList_Destroy(CircleList* list);

 //清空一个循环链表

 void CircleList_Clear(CircleList* list);

 //返回链表的长度

 int CircleList_Length(CircleList* list);

 //在POS位置插入一个节点

 int CircleList_Insert(CircleList* list, CircleListNode* node, int pos);

 //获取POS位置节点的信息

 CircleListNode* CircleList_Get(CircleList* list, int pos);

 //删除POS位置的节点

 CircleListNode* CircleList_Delete(CircleList* list, int pos);

 ////与游标相关的函数

 //删除游标所指的位置节点

 CircleListNode* CircleList_DeleteNode(CircleList* list, CircleListNode* node);

 //重置游标位置

 CircleListNode* CircleList_Reset(CircleList* list);

 //当前游标位置

 CircleListNode* CircleList_Current(CircleList* list);

 //游标的NEXT域

 CircleListNode* CircleList_Next(CircleList* list);

 #endif

 #include "circleList.h"

 #include <iostream>

 using namespace std;

 //这个为头链表头

 typedef struct _tag_CircleList

 {

     CircleListNode header;

     CircleListNode* slider;

     int length;

 }tagCircleList;

 //创建一个循环链表

 CircleList* CircleList_Create()

 {

     tagCircleList* ret = (tagCircleList*)malloc(sizeof(tagCircleList));  //分配内存

     if (ret == NULL)

     {

         return NULL;

     }

     //初始化

     ret->header.next = NULL;

     ret->length = ;

     ret->slider = NULL;

     return ret;

 }

 //删除一个循环链表

 void CircleList_Destroy(CircleList* list)

 {

     if (list = NULL)

     {

         return;

     }

     //释放内存

     free(list);

     return;

 }

 //清空一个循环链表

 void CircleList_Clear(CircleList* list)

 {

     tagCircleList* sList = NULL;

     sList = (tagCircleList*)list;

     if (sList == NULL)

     {

         return ;

     }

     //重置为初始化状态

     sList->header.next = NULL;

     sList->length = ;

     sList->slider = NULL;

     return;

 }

 //返回链表的长度

 int CircleList_Length(CircleList* list)

 {

     tagCircleList* sList = NULL;

     sList = (tagCircleList*)list;

     int ret = -;

     //异常处理

     if (list == NULL)

     {

         return ret;

     }

     return sList->length;

 }

 //在POS位置插入一个节点

 int CircleList_Insert(CircleList* list, CircleListNode* node, int pos)

 {

     tagCircleList* sList = NULL;

     sList = (tagCircleList*)list;

     int ret = -;

     //异常处理

     if(list == NULL || node == NULL || pos<)

     {

         return ret;

     }

     //临时变量Current

     CircleListNode* Current = (CircleListNode*)sList;

     for(int i = ; (i < pos) && (Current->next != NULL); i++)

     {

         Current = Current->next;

     }

     node->next = Current->next;

     Current->next = node;

     //当长度为0时 游标指向node

     if (sList->length == )

     {

         sList->slider = node;

     }

     sList->length++;

     //如果current 依旧指向链表头 证明没跳走 是从0开始插入的 需要头插法

     if (Current == (CircleListNode*)sList)

     {

         //定义一个辅助last 变量来获取尾部节点的信息

         CircleListNode* last = (CircleListNode*)CircleList_Get(sList, sList->length - );

         //将尾部节点的NEXT域存为当前节点（头节点）

         last->next = Current->next;

     }

     return ;

 }

 //获取POS位置节点的信息

 CircleListNode* CircleList_Get(CircleList* list, int pos)

 {

     tagCircleList* sList = (tagCircleList*)list;

     CircleListNode* ret = NULL;

     int i = ;

     if (list == NULL || pos < )

     {

         return NULL;

     }

     CircleListNode* Current = (CircleListNode*)sList;

     for(i = ; i < pos; i++)

     {

         Current = Current->next;

     }

     ret = Current->next;

     return ret;

 }

 //删除POS位置的节点

 CircleListNode* CircleList_Delete(CircleList* list, int pos)

 {

     tagCircleList* sList = (tagCircleList*)list;

     CircleListNode* ret = NULL;

     if ((sList != NULL) && (pos >=) && (sList->length > ))

     {

         //将Current指向表头

         CircleListNode* Current = (CircleListNode*)(&(sList->header));

         //辅助节点last 进行头节点的删除使用 存取最后一个元素

         CircleListNode* last = NULL;

         for(int i = ; i < pos; i++)

         {

             Current = Current->next;

         }

         //删除头结点

         if ( Current == (CircleListNode*)sList)

         {

             last = (CircleListNode*)CircleList_Get(sList, sList->length - );

         }

         //要删除的元素

         ret = Current->next;

         Current->next = ret->next;

         sList->length--;

         //判断链表非空

         if( last != NULL)

         {

             //sList->header.next = ret->next;

             Current->next = ret->next;

             last->next = ret->next;

         }

         //若删除的元素为游标所指的元素

         if(sList->slider = ret)

         {

             sList->slider = ret->next;

         }

         //若删除元素后 链表长度为0 做处理

         if (sList->length == )

         {

             sList->header.next = NULL;

             sList->slider = NULL;

         }

     }

     return ret;

 }

 ////与游标相关的函数

 //删除游标所指的位置节点

 CircleListNode* CircleList_DeleteNode(CircleList* list, CircleListNode* node)

 {

     tagCircleList* sList = (tagCircleList*)list;

     CircleListNode* ret = NULL;

     int i = ;

     if (sList != NULL)

     {

         CircleListNode* Current = (CircleListNode*)sList;

         //循环查找node 在链表中的位置

         for (i = ; i < sList->length; i++)

         {

             if (Current->next == node)

             {

                 ret = Current->next;

                 break;

             }

             Current = Current->next;

         }

         //找到了 使用CircleList_Delete 删除

         if(ret != NULL)

         {

             CircleList_Delete(list, i);

         }

     }

     return ret;

 }

 //重置游标位置

 CircleListNode* CircleList_Reset(CircleList* list)

 {

     tagCircleList* sList = (tagCircleList*)list;

     CircleListNode* ret = NULL;

     //如果不为空

     if (sList != NULL)

     {

         sList->slider = sList->header.next;

         ret = sList->slider;

     }

     return ret;

 }

 //当前游标位置

 CircleListNode* CircleList_Current(CircleList* list)

 {

     tagCircleList* sList = (tagCircleList*)list;

     CircleListNode* ret = NULL;

     //如果不为空

     if (sList != NULL)

     {

         ret = sList->slider;

     }

     return ret;

 }

 //把游标位置返回，游标下移

 CircleListNode* CircleList_Next(CircleList* list)

 {

     tagCircleList* sList = (tagCircleList*)list;

     CircleListNode* ret = NULL;

     //如果不为空

     if((sList != NULL) && (sList->slider != NULL))

     {

         ret = sList->slider;

         sList->slider = ret->next;

     }

     return ret;

 }

#include "circleList.h"

#include <iostream>

using namespace std;

typedef struct _Temp_Test

{

    CircleListNode node;

    int temp;

    char temp2;

}TempTast;

int main()

{

    CircleList* circlelist = NULL;

    circlelist = CircleList_Create();

    //异常处理

    if (circlelist == NULL)

    {

        cout << "Create Err "  << endl;

        return -;

    }

    TempTast t1, t2, t3, t4, t5;

    t1.temp = ;

    t2.temp = ;

    t3.temp = ;

    t4.temp = ;

    t5.temp = ;

    //插入元素

    CircleList_Insert(circlelist, (CircleListNode*)(&t1), );

    CircleList_Insert(circlelist, (CircleListNode*)(&t2), );

    CircleList_Insert(circlelist, (CircleListNode*)(&t3), );

    CircleList_Insert(circlelist, (CircleListNode*)(&t4), );

    CircleList_Insert(circlelist, (CircleListNode*)(&t5), );

    //测试功能

    cout << "Length: " << CircleList_Length(circlelist) << endl;

    //遍历两次

    cout << "遍历两次:" << endl;

    for(int i = ; i < *CircleList_Length(circlelist); i++)

    {

        cout <<"Node:" << ((TempTast*)CircleList_Get(circlelist, i))->temp << endl;

    }

    cout << endl;

    //删除第一个节点

    cout <<"Node:" << ((TempTast*)CircleList_Delete(circlelist, ))->temp << endl;

    //清空

    CircleList_Clear(circlelist);

    cout << "After Clear Length: " << CircleList_Length(circlelist) << endl;

    //插入元素

    CircleList_Insert(circlelist, (CircleListNode*)(&t1), );

    CircleList_Insert(circlelist, (CircleListNode*)(&t2), );

    CircleList_Insert(circlelist, (CircleListNode*)(&t3), );

    CircleList_Insert(circlelist, (CircleListNode*)(&t4), );

    CircleList_Insert(circlelist, (CircleListNode*)(&t5), );

    //删除指定元素

    cout << "Delete Node :" << ((TempTast*)CircleList_DeleteNode(circlelist, (CircleListNode*)(&t1)))->temp << endl;

    //显示游标当前位置

    cout << "Silder Now :" << ((TempTast*)CircleList_Current(circlelist))->temp << endl;

    //移动后

    CircleList_Next(circlelist);

    cout << "Silder After Next :" << ((TempTast*)CircleList_Current(circlelist))->temp << endl;

    //重置后

    CircleList_Reset(circlelist);

    cout << "Silder After Reset :" << ((TempTast*)CircleList_Current(circlelist))->temp << endl;

    cout << endl;

    //销毁

    CircleList_Destroy(circlelist);

    cout << "circle has been Destroied" << endl;

    system("pause");

    return ;

}