带头结点循环链表

上一个说的是单链表，其实循环链表跟单链表类似，单链表最后一个节点(p)的next域为NULL即p->next=NULL而循环链表(plist)的则为头结点的地址，即p->next=plist。其余的基本操作和单链表几乎一样，仅仅是单链表循环结束条件为!=NULL，而循环链表是!=plist。

基本操作为：初始化，插入（头插、尾插），查找，删除，判空，求长，摧毁，逆置。

.cpp:

#include <stdio.h>#include <stdlib.h>#include <assert.h>#include "clist.h"void InitList(CList plist){assert(plist != NULL);if(plist == NULL){return ;}plist->next = plist;//循环链表}//头插bool Insert_Head(CList plist,int val){CNode *p = (CNode *)malloc(sizeof(CNode));assert(p != NULL);//p->data = val;p->next = plist->next;//plist->next = p;return true;}//尾插bool Insert_Tail(CList plist,int val){CNode *p;for(p=plist;p->next!=plist;p=p->next){;}CNode *q = (CNode *)malloc(sizeof(CNode));q->data = val;//q插在p的后面q->next = p->next;//q->next = plist;p->next = q;return true;}CNode *Search(CList plist,int key)//List {for(CNode *p=plist->next;p!=plist;p=p->next){if(p->data == key){return p;}}return NULL;}bool Delete(CList plist,int key){CNode *p = Search(plist,key);CNode *q;if(p == NULL){return false;}if(p->next != plist)//p不是最后的节点,删除p后面的点，将后面的数据赋值到p中{q = p->next;p->next = q->next;p->data = q->data;free(q);}else//p是最后一个点{for(q=plist;q->next!=p;q=q->next) ;//找到p的前驱，然后删除pq->next = p->next;free(p);}return true;}bool IsEmpty(CList plist){return plist->next == plist;}int GetLength(CList plist){int count = 0;for(CNode *p=plist->next;p!=plist;p=p->next){count++;}return count;}void Show(CList plist){for(CNode *p=plist->next;p!=plist;p=p->next){printf("%d ",p->data);}printf("\n");}void Clear(CList plist){Destroy(plist);}void Destroy(CList plist){CNode *p;while(plist->next != plist){p = plist->next;plist->next = p->next;free(p);}}void Revers(CList plist){if(plist==NULL||plist->next==NULL||plist->next->next==NULL){return;}CNode *p=plist->next;CNode *q;plist->next=plist;while(p!=plist){q=p->next;p->next=plist->next;plist->next=p;p=q;}}

.h:

#pragma once//循环链表,尾节点的next指向头节点typedef struct CNode{int data;struct CNode *next;}CNode,*CList;void InitList(CList plist);//Node *plist//头插bool Insert_Head(CList plist,int val);//尾插bool Insert_Tail(CList plist,int val);CNode *Search(CList plist,int key);//List bool Delete(CList plist,int key);bool IsEmpty(CList plist);int GetLength(CList plist);void Show(CList plist);void Clear(CList plist);void Destroy(CList plist);void Revers(CList plist);