一步一步学数据结构之1--1（循环链表）

来源：互联网发布：windows企业版激活编辑：程序博客网时间：2024/06/10 15:21

今天记录下循环链表，其实循环链表也就是将单链表中最后一个数据元素的next指针指向第一个元素。

这里有一个概念需要说明下：

游标：在循环链表中可以定义一个“当前”指针，这个指针通常称为游标，可以通过这个游标来遍历链表中的所有元素

如图

这里介绍静态链表的常用操作：

l 创建循环链表

l 销毁循环链表

l 清空循环链表

l 获取表长度

l 把node插入pos位置

l 获取pos位置的元素

l 删除pos位置的元素

l 删除表中与node相同的元素（删除第一个匹配成功的）

l 重置游标

l 返回游标所指向的结点

l 游标后移

代码总分为三个文件：

CircleList.h ：放置功能函数的声明，以及表的声明，表结点的定义

CircleList.c ：放置功能函数的定义，以及表的定义

Main.c ：主函数，使用功能函数完成各种需求，不过一般用作测试

整体结构图为：

这里详细说下插入操作和删除操作：

插入操作：

如图

插入元素方法：

判断表和插入位置是否合法

由表头开始通过next域移动pos次后，当前元素的next域为要插入的位置

将新元素插入（和单链表插入方法相同）

表长度加1

判断是否为头插（就是头结点和首元素中间插入）

如果是头插的话，把尾结点的next域指向第一个元素（也就是头节点所指向的首元素）

如果之前表为空表，则游标指向插入的结点

删除操作：

如图

删除元素方法：

判断表和插入位置是否合法

由表头开始通过next域移动pos次后，当前元素的next指向的元素为要删除的元素

删除元素（和单链表删除元素相同）

表长度减1

判断是否删除的为首元素

如果删除的是首元素的话，把表尾结点的next域指向首元素

如果删除后表为空，则重置头结点的next域和游标

如果删除的结点正好游标也指向它，则游标后移

OK! 上代码：

CircleList.h

#ifndef _CIRCLELIST_H_#define _CIRCLELIST_H_typedef void CircleList;typedef struct _tag_CircleListNode CircleListNode;struct _tag_CircleListNode{CircleListNode* next;};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

CircleList.c

#include <stdio.h>#include <malloc.h>#include "CircleList.h"typedef struct _tag_CircleList{CircleListNode header;CircleListNode* slider;int length;}TCircleList;CircleList* CircleList_Create(){TCircleList* sList = (TCircleList*)malloc(sizeof(TCircleList));if(NULL != sList){sList->header.next = NULL;sList->slider = NULL;sList->length = 0;}return sList;}void CircleList_Destroy(CircleList* list){free(list);}void CircleList_Clear(CircleList* list){TCircleList* sList = (TCircleList*)list;if(NULL != sList){sList->header.next = NULL;sList->slider = NULL;sList->length = 0;}}int CircleList_Length(CircleList* list){TCircleList* sList = (TCircleList*)list;int ret = -1;if(NULL != sList){ret = sList->length;}return ret;}int CircleList_Insert(CircleList* list, CircleListNode* node, int pos){TCircleList* sList = (TCircleList*)list;int ret = (NULL!=sList)&&(NULL!=node)&&(0<=pos);int i = 0;if(ret){CircleListNode* current = (CircleListNode*)sList;for(i=0; (i<pos)&&(current->next!=NULL); i++){current = current->next;}node->next = current->next;current->next = node;if(0 == sList->length){sList->slider = node;}sList->length++;if(current == (CircleListNode*)sList){CircleListNode* last = CircleList_Get(sList, sList->length-1);last->next = current->next;}}return ret;}CircleListNode* CircleList_Get(CircleList* list, int pos){TCircleList* sList = (TCircleList*)list;CircleListNode* ret = NULL;int i = 0;if((NULL != sList)&&(0 < sList->length)){CircleListNode* current = (CircleListNode*)sList;for(i=0; i<pos; i++){current = current->next;}ret = current->next;}return ret;}CircleListNode* CircleList_Delete(CircleList* list, int pos){TCircleList* sList = (TCircleList*)list;CircleListNode* ret = NULL;int i = 0;if((NULL != sList)&&(0 <= pos)&&(0 < sList->length)){CircleListNode* current = (CircleListNode*)sList;CircleListNode* last = NULL;for(i=0; i<pos; i++){current = current->next;}ret = current->next;current->next = ret->next;sList->length--;if(current == (CircleListNode*)sList){last = (CircleListNode*)CircleList_Get(sList, sList->length-1);}if(NULL != last){sList->header.next = ret->next;last->next = ret->next;}if(ret == sList->slider){sList->slider = ret->next;}if(0 == sList->length){sList->slider = NULL;sList->header.next = NULL;}}return ret;}CircleListNode* CircleList_DeleteNode(CircleList* list, CircleListNode* node){TCircleList* sList = (TCircleList*)list;CircleListNode* ret = NULL;int i = 0;if((NULL != sList)&&(NULL != node)){CircleListNode* current = (CircleListNode*)sList;for(i=0; i<sList->length; i++){if(node == current->next){ret = current->next;break;}current = current->next;}if(NULL != ret){CircleList_Delete(sList, i);}}return ret;}CircleListNode* CircleList_Reset(CircleList* list){TCircleList* sList = (TCircleList*)list;CircleListNode* ret = NULL;if(NULL != sList){sList->slider = sList->header.next;ret = sList->slider;}return ret;}CircleListNode* CircleList_Current(CircleList* list){TCircleList* sList = (TCircleList*)list;CircleListNode* ret = NULL;if(NULL != sList){ret = sList->slider;}return ret;}CircleListNode* CircleList_Next(CircleList* list){TCircleList* sList = (TCircleList*)list;CircleListNode* ret = NULL;if(NULL != sList){ret = sList->slider;sList->slider = ret->next;}return ret;}

Main.c

#include <stdio.h>#include <stdlib.h>#include "CircleList.h"typedef struct _tag_Value{CircleListNode header;int v;}Value;int main(void){int i = 0;CircleList* list = CircleList_Create();Value v1,v2,v3,v4,v5,v6,v7,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));CircleList_Insert(list, (CircleListNode*)&v5, 5);CircleList_Delete(list, 0);for(i=0; i<2*CircleList_Length(list); i++){Value* p = (Value*)CircleList_Get(list, i);printf("%d ", p->v);}printf("\n");while(CircleList_Length(list) > 0){Value* p = (Value*)CircleList_Delete(list, 0);printf("%d ", p->v);}printf("\n");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));CircleList_Insert(list, (CircleListNode*)&v5, CircleList_Length(list));CircleList_Insert(list, (CircleListNode*)&v6, CircleList_Length(list));CircleList_Insert(list, (CircleListNode*)&v7, CircleList_Length(list));CircleList_Insert(list, (CircleListNode*)&v8, CircleList_Length(list));for(i=0; i<CircleList_Length(list); i++){Value* p = (Value*)CircleList_Next(list);printf("%d ", p->v);}printf("\n");CircleList_Reset(list);while(CircleList_Length(list) > 0){Value* pV = NULL;for(i=1; i<3; i++){CircleList_Next(list);}pV = (Value*)CircleList_Current(list);printf("%d\n", pV->v);CircleList_DeleteNode(list, (CircleListNode*)pV);}CircleList_Destroy(list);return 0;}