用C语言实现循环链表

将单项链表的尾节点指针指向此链表的头结点，即组成了循环链表。

具体实现代码如下【C语言，在vs开发工具下调试通过】

源码分三个文件，分别为CircleLinkList.h CircleLinkList.c main.c

CircleLinkList.h源码：

#ifndef CIRCLELINKLIST
#define CIRCLELINKLIST
#include<stdio.h>
#include<stdlib.h>

//链表的小结点
typedef struct CIRCLELINKNODE{
struct CIRCLELINKNODE* next;
}CircleLinkNode;

//链表结构体
typedef struct CIRCLELINKLIST{
CircleLinkNode head;
int size;
}CircleLinkList;

//编写针对链表结构体操作的API函数

#define CIRCLELINKLIST_TRUE 1
#define CIRCLELINKLIST_FALSE 0

//比较回调
typedef int(*COMPARENODE)(CircleLinkNode*, CircleLinkNode*);
//打印回调
typedef void(*PRINTNODE)(CircleLinkNode*);

//初始化函数
CircleLinkList* Init_CircleLinkList();
//插入函数
void Insert_CircleLinkList(CircleLinkList* clist, int pos, CircleLinkNode* data);
//获得第一个元素
CircleLinkNode* Front_CircleLinkList(CircleLinkList* clist);
//根据位置删除
void RemoveByPos_CircleLinkList(CircleLinkList* clist,int pos);
//根据值去删除
void RemoveByValue_CircleLinkList(CircleLinkList* clist, CircleLinkNode* data, COMPARENODE compare);
//获得链表的长度
int Size_CircleLinkList(CircleLinkList* clist);
//判断是否为空
int IsEmpty_CircleLinkList(CircleLinkList* clist);
//查找
int Find_CircleLinkList(CircleLinkList* clist, CircleLinkNode* data, COMPARENODE compare);
//打印节点
void Print_CircleLinkList(CircleLinkList* clist, PRINTNODE print);
//释放内存
void FreeSpace_CircleLinkList(CircleLinkList* clist);

#endif

CircleLinkList.c源码：

#include"CircleLinkList.h"

//初始化函数
CircleLinkList* Init_CircleLinkList(){

CircleLinkList* clist = (CircleLinkList*)malloc(sizeof(CircleLinkList));
clist->head.next = &(clist->head);
clist->size = 0;
return clist;
}

//插入函数
void Insert_CircleLinkList(CircleLinkList* clist, int pos, CircleLinkNode* data){

if (clist == NULL){
return;
}

if (data == NULL){
return;
}

if (pos <0 || clist->size){
pos = clist->size;
}

//根据位置查找结点
//辅助指针变量
CircleLinkNode* pCurrent = &(clist->head);
for (int i = 0; i < pos;i++){
pCurrent = pCurrent->next;
}

//新数据入链表
data->next = pCurrent->next;
pCurrent->next = data;

clist->size ++;
}
//获得第一个元素
CircleLinkNode* Front_CircleLinkList(CircleLinkList* clist){
return clist->head.next;
}
//根据位置删除
void RemoveByPos_CircleLinkList(CircleLinkList* clist, int pos){

if (clist == NULL){
return;
}

if (pos < 0 || pos >= clist->size){
return;
}

//根据pos找结点
//辅助指针变量
CircleLinkNode* pCurrent = &(clist->head);
for (int i = 0; i < pos;i++){
pCurrent = pCurrent->next;
}

//缓存当前结点的下一个结点
CircleLinkNode* pNext = pCurrent->next;
pCurrent->next = pNext->next;

clist->size--;
}
//根据值去删除
void RemoveByValue_CircleLinkList(CircleLinkList* clist, CircleLinkNode* data, COMPARENODE compare){

if (clist == NULL){
return;
}

if (data == NULL){
return;
}

//这个是循环链表
CircleLinkNode* pPrev = &(clist->head);
CircleLinkNode* pCurrent = pPrev->next;
int i = 0;
for (i = 0; i < clist->size; i++){
if (compare(pCurrent, data) == CIRCLELINKLIST_TRUE){
pPrev->next = pCurrent->next;
clist->size--;
break;
}
pPrev = pCurrent;
pCurrent = pPrev->next;
}
}
//获得链表的长度
int Size_CircleLinkList(CircleLinkList* clist){
return clist->size;
}
//判断是否为空
int IsEmpty_CircleLinkList(CircleLinkList* clist){
if (clist->size == 0){
return CIRCLELINKLIST_TRUE;
}
return CIRCLELINKLIST_FALSE;
}
//查找
int Find_CircleLinkList(CircleLinkList* clist, CircleLinkNode* data, COMPARENODE compare){

if (clist == NULL){
return -1;
}

if (data == NULL){
return -1;
}

CircleLinkNode* pCurrent = clist->head.next;
int flag = -1;
for (int i = 0; i < clist->size; i ++){
if (compare(pCurrent,data) == CIRCLELINKLIST_TRUE){
flag = i;
break;
}
pCurrent = pCurrent->next;
}

return flag;
}
//打印节点
void Print_CircleLinkList(CircleLinkList* clist, PRINTNODE print){

if (clist == NULL){
return;
}

//辅助指针变量
CircleLinkNode* pCurrent = clist->head.next;
for (int i = 0; i < clist->size;i++){
if (pCurrent == &(clist->head)){
pCurrent = pCurrent->next;
printf("------------------\n");
}
print(pCurrent);
pCurrent = pCurrent->next;
}
}
//释放内存
void FreeSpace_CircleLinkList(CircleLinkList* clist){

if (clist == NULL){
return;
}
acf8
free(clist);
}
</0>

main.c源码：

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include"CircleLinkList.h"

typedef struct PERSON{
CircleLinkNode node;
char name[64];
int age;
int score;
}Person;

void MyPrint(CircleLinkNode* data){
Person* p = (Person*)data;
printf("Name:%s Age:%d Score:%d\n",p->name,p->age,p->score);
}

int MyCompare(CircleLinkNode* data1, CircleLinkNode* data2){
Person* p1 = (Person*)data1;
Person* p2 = (Person*)data2;

if (strcmp(p1->name,p2->name) ==0 && p1->age == p2->age&& p1->score == p2->score){
return CIRCLELINKLIST_TRUE;
}
return CIRCLELINKLIST_FALSE;
}

int main(void){

//创建循环链表
CircleLinkList* clist = Init_CircleLinkList();

//创建数据
Person p1, p2, p3, p4, p5;
strcpy(p1.name, "aaa");
strcpy(p2.name, "bbb");
strcpy(p3.name, "ccc");
strcpy(p4.name, "ddd");
strcpy(p5.name, "eee");

p1.age = 10;
p2.age = 20;
p3.age = 30;
p4.age = 40;
p5.age = 50;

p1.score = 50;
p2.score = 50;
p3.score = 60;
p4.score = 65;
p5.score = 70;

//数据入链表
Insert_CircleLinkList(clist, 100, (CircleLinkNode*)&p1);
Insert_CircleLinkList(clist, 100, (CircleLinkNode*)&p2);
Insert_CircleLinkList(clist, 100, (CircleLinkNode*)&p3);
Insert_CircleLinkList(clist, 100, (CircleLinkNode*)&p4);
Insert_CircleLinkList(clist, 100, (CircleLinkNode*)&p5);

//打印
Print_CircleLinkList(clist, MyPrint);

Person pDel;
strcpy(pDel.name,"ddd");
pDel.age = 40;
pDel.score = 65;

//根据值删除
RemoveByValue_CircleLinkList(clist, (CircleLinkNode*)&pDel, MyCompare);

//打印
printf("--------------\n");
Print_CircleLinkList(clist, MyPrint);

//释放内存
FreeSpace_CircleLinkList(clist);

system("pause");
return 0;
}