循环链表的实现与操作(C语言实现)

循环链表是另一种形式的链式存贮结构。它的特点是表中最后一个结点的指针域指向头结点，整个链表形成一个环。

循环链表的操作

1,循环链表的新操作

2, 获取当前游标指向的数据元素

3, 将游标重置指向链表中的第一个数据元素

4,将游标移动指向到链表中的下一个数据元素

5,直接指定删除链表中的某个数据元素

CircleListNode* CircleList_DeleteNode(CircleList* list, CircleListNode* node);
CircleListNode* CircleList_Reset(CircleList* list);
CircleListNode* CircleList_Current(CircleList* list);
CircleListNode* CircleList_Next(CircleList* list);

头文件：

#ifndef _CIRCLE_H_#define _CIRCLE_H_//采用数据封装的方式，防止在主函数修改其中的属性值(有点点像面向对象中的私有属性)typedef void CircleList;typedef struct CircleListNode   //声明指针域{CircleListNode * next;}CircleListNode;CircleList * CircleList_Create();void CircleList_DesTroy(CircleList * list);void CircleList_Clear(CircleList* list);int CircleList_Length(CircleList* list);int CircleList_Insert(CircleList* list, CircleListNode* node, int pos);CircleListNode* CircleList_Get(CircleList* list, int pos);CircleListNode* CircleList_Delete(CircleList* list, int pos);CircleListNode* CircleList_DeleteNode(CircleList* list, CircleListNode* node);CircleListNode* CircleList_Reset(CircleList* list);CircleListNode* CircleList_Current(CircleList* list);CircleListNode* CircleList_Next(CircleList* list) ;#endif 

源文件：

// 循环链表.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"#include <malloc.h>#include <stdlib.h>#include "CircleList.h"typedef struct   //定义头结点{      CircleListNode header;   CircleListNode* sLider;  //游标   int len;}TCircleList;struct Value        //定义数据结构体类型{    CircleListNode header;  //指针域    int v;                //数据域};int _tmain(int argc, _TCHAR* argv[]){     int i = 0;    CircleList* list = CircleList_Create();        struct Value v1;    struct Value v2;    struct Value v3;    struct Value v4;    struct Value v5;    struct Value v6;    struct Value v7;    struct Value v8;           v1.v = 1;    v2.v = 2;    v3.v = 3;    v4.v = 4;    v5.v = 5;    v6.v = 6;    v7.v = 7;    v8.v = 8;        CircleList_Insert(list, (CircleListNode*)&v1, CircleList_Length(list));    CircleList_Insert(list, (CircleListNode*)&v2, CircleList_Length(list));    CircleList_Insert(list, (CircleListNode*)&v3, CircleList_Length(list));    CircleList_Insert(list, (CircleListNode*)&v4, CircleList_Length(list));//插入到 5 的位置，前面的顺序为 1->2->3->4  //                      下标： 0  1  2  3//                             4  5 ...//故而插入到 5 的位置时  打印的结果应为 ：  1,5,2,3,4，后面的结果也验证了其正确性    CircleList_Insert(list, (CircleListNode*)&v5, 5);        for(i=0; i<CircleList_Length(list); i++)    {        struct Value* pv = (struct Value*)CircleList_Get(list, i);                printf("%d\n", pv->v);    }        while( CircleList_Length(list) > 0 )    {        struct Value* pv = (struct Value*)CircleList_Delete(list, 0);                printf("删除了：%d\n", pv->v);    }        CircleList_DesTroy(list);system("pause");return 0;}//创建CircleList * CircleList_Create(){TCircleList* list = (TCircleList*)malloc(sizeof(TCircleList));if(NULL != list){list->sLider = NULL;list->header.next = NULL;list->len = 0;}return list;}//销毁void CircleList_DesTroy(CircleList * list){free(list);}//清空void CircleList_Clear(CircleList* list){TCircleList * sList = (TCircleList*)list;if(NULL != sList){sList->len = 0;sList->header.next = NULL;sList->sLider = NULL;}}//获得长度int CircleList_Length(CircleList* list){TCircleList * sList = (TCircleList*)list;int len = -1;if(NULL != sList){len = sList->len;}return len;}//插入  int CircleList_Insert(CircleList* list, CircleListNode* node, int pos)  {  TCircleList * sList = (TCircleList*)list;  int i = 0;  int ret = 0;  sList->len;  if((NULL != sList) && (pos>=0) && (NULL != node))  {      CircleListNode * current = (CircleListNode*)sList;      for ( i=0; i<pos && current->next != NULL; i++)      {      current = current->next;      }            node->next = current->next;             current->next = node;      if(sList->len == 0)      {      sList->sLider = node;            }      ++(sList->len);      if( current == (CircleListNode*)sList )      {      CircleListNode* last = CircleList_Get(sList, sList->len - 1);                  last->next = current->next;      }      ret = 1;              }  return ret;  }  //获得结点CircleListNode* CircleList_Get(CircleList* list, int pos){TCircleList * sList = (TCircleList*)list;CircleListNode * resNode = NULL;int i = 0;if((NULL != sList) && (pos>=0)){CircleListNode * current = (CircleListNode*)sList;for( i=0; i<pos; i++){//i=0时，current为头结点，current->next为真正的第一个结点current = current->next;}resNode = current->next;}return resNode;}//删除CircleListNode* CircleList_Delete(CircleList* list, int pos){TCircleList * sList = (TCircleList*)list;int i = 0;CircleListNode * resnode = NULL;CircleListNode* first = sList->header.next;CircleListNode* last = (CircleListNode*)CircleList_Get(list,sList->len-1);if((NULL != sList) && (pos >= 0) && (pos < sList->len)){CircleListNode * current = (CircleListNode*)sList;for ( i=0; i<pos; i++){//i=0时，current为头结点，current->next为真正的第一个结点current = current->next;}resnode = current->next;current->next = resnode->next;if(first == resnode){sList->header.next = first->next;last->next = first->next;}if(sList->sLider == resnode){sList->sLider = resnode->next;}if(sList->len == 0){sList->header.next = NULL;sList->sLider = NULL;}}sList->len--;return resnode;}//根据结点来删除CircleListNode* CircleList_DeleteNode(CircleList* list, CircleListNode* node){TCircleList * sList = (TCircleList*)list;CircleListNode* resnode = NULL;int i = 0;if(NULL != sList){CircleListNode* current = (CircleListNode*)sList;for ( i=0; i<sList->len; i++){if(node == current->next){resnode = current->next;break;}current = current->next;}if(NULL != resnode){CircleList_Delete(sList,i);}}return resnode;}//将游标重置回第一个元素CircleListNode* CircleList_Reset(CircleList* list) {    TCircleList* sList = (TCircleList*)list;    CircleListNode* ret = NULL;        if( sList != NULL )    {sList->sLider= sList->header.next;        ret = sList->sLider;    }        return ret;}//获得当前游标下的结点CircleListNode* CircleList_Current(CircleList* list) {    TCircleList* sList = (TCircleList*)list;    CircleListNode* ret = NULL;sList->len;sList->header;sList->sLider;    if( sList != NULL )    {ret = sList->sLider;    }        return ret;}//将游标移到下一个结点并获得当前移动前的结点CircleListNode* CircleList_Next(CircleList* list) {    TCircleList* sList = (TCircleList*)list;    CircleListNode* ret = NULL;    if( (sList != NULL) && (sList->sLider != NULL) )    {        ret = sList->sLider;        sList->sLider = ret->next;    }        return ret;}

运行结果：

15234删除了：1删除了：5删除了：2删除了：3删除了：4请按任意键继续. . .

如有错误，望不吝指出。