双向循环链表 C语言通用编程的思考

#include <stdio.h>#include <math.h>#include <string.h>#include <stdlib.h>//基于双向循环链表的例子#define PDATA void*//#define DEBUG//定义用户结构体数据/*typedef struct Staff{int id;float wages;}UserData;*/typedef struct Student{int id;char name[20];char sex[10];int score;}UserData;//输入信息void inputInfo(UserData *usrData);void printInfo(UserData usrData);/*-----------双向循环链表结点数据结构---------*/typedef struct DcllNode{PDATA pdate;//结点数据指针DcllNode * pre;//指向前个结点的指针DcllNode * next;//指向后个结点的指针}*pNode,Node;/*-------------------------------------------*//*------------双向循环链表数据结构-----------*/typedef struct Dcll{pNode virBegin;//虚拟表头指针pNode virEnd;//虚拟表尾指针int nodeNum;//结点计数}*pDcll,Dcll;/*-------------------------------------------*//*--------------双向循环链表全局变量---------*/Dcll dclnkList;/*-------------------------------------------*//*--------------双向循环链表操作-------------*/void DnitDcll();//初始化双向循环链表void InsertNode(pNode insNode,pNode usrDatartPos,int shift);//在当前状态位置移位后位置插入结点pNode DeleteNode(pNode usrDatartPos,int shift);//在当前状态位置移位后位置删除结点pNode GetNodeP(pNode usrDatartPos,int shift);//得到当前状态位置移位后位置void DeleteCurNode(pNode curPos);//删除当前指针所指结点int Delete_if(pNode delnode,void *iffunc);//按条件删除结点void InsertCurNode(pNode insNode,pNode usrDatartPos);//在当前位置加入结点int GetNodesNum();//得到双向循环链表结点个数void InsertTailNode(pNode insNode);//尾插入结点void InsertHeadNode(pNode insNode);//头插入结点void Insert_if(pNode insNode,void *iffunc);//按条件插入数据int if_function(pNode pnode,pNode);//条件函数int compare(void * arg1,void * arg2);//比较函数void printNode(pNode);//输出结点信息void List(pNode);//输出双向循环链表内容int isDeleted(pNode pnode,pNode delNode);//删除判定函数/*------------------------------------------*///主函数int main(){int i;float maxWages = 0;pNode pnode = NULL;for(i = 0; i < 5; ++i){pnode = (pNode)malloc(sizeof(Node));pnode->pdate = malloc(sizeof(UserData));inputInfo((UserData *)(pnode->pdate));Insert_if(pnode,if_function);#ifdef DEBUGList(dclnkList.virBegin);//printInfo(*(usrData+i));#endif}//List(dclnkList.virBegin);//printf("输出/n");pnode = (pNode)malloc(sizeof(Node));pnode->pdate = malloc(sizeof(UserData));scanf("%d",&(((UserData *)(pnode->pdate))->score));strcpy(((UserData *)(pnode->pdate))->name ,"aaa");strcpy(((UserData *)(pnode->pdate))->sex ,"male");((UserData *)(pnode->pdate))->id = 180;if(Delete_if(pnode,isDeleted) == 0) {InsertTailNode(pnode);}List(dclnkList.virBegin);return 0;}void DnitDcll(){dclnkList.nodeNum = 0;//结点数置零dclnkList.virBegin = dclnkList.virEnd = NULL;//初始虚拟开始结点及虚拟结束结点}//从当前位置移动shift个位置pNode GetNodeP(pNode usrDatartPos,int shift = 0){//没有数据时if(dclnkList.nodeNum == 0)return NULL;if(shift == 0)return usrDatartPos;int loop;int shfNum = abs(shift);pNode curPos = usrDatartPos;if(shift > 0)//向后移{for(loop = 0;loop < shfNum; ++loop){curPos = curPos->next;}return curPos;}else{for(loop = 0;loop < shfNum; ++loop){curPos = curPos->pre;}return curPos;}}//void InsertCurNode(pNode insNode,pNode usrDatartPos){//当加入第一个数据时if(dclnkList.virBegin == NULL){dclnkList.virBegin = dclnkList.virEnd = insNode;//让其指向自己insNode->next=insNode;insNode->pre=insNode;++dclnkList.nodeNum;return;}//更新四个基本的链接insNode->pre = usrDatartPos;insNode->next = usrDatartPos->next;insNode->next->pre = insNode;usrDatartPos->next = insNode;//对虚拟链首及链尾的更新if(usrDatartPos == dclnkList.virEnd){dclnkList.virEnd = usrDatartPos->next;}//更新结点个数++dclnkList.nodeNum;}//删除当前结点void DeleteCurNode(pNode curPos){//如果当前只有一个结点if(dclnkList.nodeNum == 1){dclnkList.virBegin = dclnkList.virEnd = NULL;--dclnkList.nodeNum;//释放当前待删除结点所占空间free(curPos->pdate);free(curPos);return ;}curPos->next->pre = curPos->pre;curPos->pre->next = curPos->next;--dclnkList.nodeNum;//更新链首、链尾if(curPos == dclnkList.virBegin){dclnkList.virBegin = curPos->next;}if(curPos == dclnkList.virEnd){dclnkList.virEnd = curPos->pre;}//释放当前待删除结点所占空间free(curPos->pdate);free(curPos);}void InsertNode(pNode insNode,pNode usrDatartPos,int shift){InsertCurNode(insNode,GetNodeP(usrDatartPos,shift));}pNode DeleteNode(pNode usrDatartPos,int shift = 0){pNode pnode = GetNodeP(usrDatartPos,shift);DeleteCurNode(pnode);return pnode;}int GetNodesNum(){return dclnkList.nodeNum;}void InsertTailNode(pNode insNode){InsertCurNode(insNode,dclnkList.virEnd);//dclnkList.virEnd = dclnkList.virEnd->next;}void InsertHeadNode(pNode insNode){InsertTailNode(insNode);dclnkList.virBegin = dclnkList.virEnd;//此时已更新了虚拟结束节点，要重设结束节点dclnkList.virEnd = dclnkList.virEnd->pre;}int if_function(pNode pnode1,pNode pnode2){//printf("执行判断/n");if(pnode2 == NULL)return 1;return compare(pnode1->pdate,pnode2->pdate);}void Insert_if(pNode insNode,void *iffunc){if(dclnkList.nodeNum == 0){InsertHeadNode(insNode);return;}if(if_function(insNode,dclnkList.virBegin)){#ifdef DEBUGprintf("加在beginnode 前/n");#endifInsertHeadNode(insNode);return;}if(!if_function(insNode,dclnkList.virEnd)){#ifdef DEBUGprintf("加在endnode后/n");#endifInsertTailNode(insNode);return;}pNode curP = dclnkList.virBegin->next;//int condition = ((*(void (*)(pNode,pNode))iffunc)(insNode,curP));int condition = (*((int (*)(pNode,pNode))(iffunc)))(insNode,curP);int i = 0;while(i < dclnkList.nodeNum && !condition){curP = curP->next;condition = (*((int (*)(pNode,pNode))(iffunc)))(insNode,curP);++i;}InsertCurNode(insNode,curP->pre);}int Delete_if(pNode delnode,void *iffunc){pNode pnode = dclnkList.virBegin;pNode tmp;int count = 0;//用于计数int i;for(i = 0 ;i < dclnkList.nodeNum ; ++i){if( (*(int(*)(pNode,pNode))(iffunc))(delnode,pnode) ){count++;tmp = pnode->next;DeleteCurNode(pnode);pnode = tmp;continue;}pnode = pnode->next;}return count;}void List(pNode pnode){pNode tmp = pnode;int i;#ifdef DEBUGprintf("共%d个结点/n",dclnkList.nodeNum);#endiffor(i = 0;i < dclnkList.nodeNum; ++i){#ifdef DEBUGprintf("第%d个结点/n",i+1);#endifprintNode(tmp);tmp = tmp->next;}}void printNode(pNode pnode){printInfo(*((UserData *)(pnode->pdate)));}/*-----------------用户函数-----------------*/int compare(void * arg1,void * arg2){if(arg2 == NULL)return 0;UserData * usrData1 = (UserData *)arg1;UserData * usrData2 = (UserData *)arg2;if(usrData1->id <= usrData2->id)return 1;return 0;}int isDeleted(pNode pnode,pNode delNode){if( ((UserData *)(pnode->pdate))->score == ((UserData *)(delNode->pdate))->score ){return 1;}return 0;}void inputInfo(UserData *usrData){//scanf("%d%f",&usrData->id,&usrData->wages);scanf("%d",&usrData->id);scanf("%s",&usrData->name);scanf("%s",&usrData->sex);scanf("%d",&usrData->score);getchar();}void printInfo(UserData usrData){//printf("%d/n%.2f/n",usrData.id,usrData.wages);printf("%d/n%s/n%s/n%d/n",usrData.id,usrData.name,usrData.sex,usrData.score); 

一个双向循环链表的小例子，包含了链表的大部分操作。有一定的通用性，足能应付链表操作。

用到了一些 void *指针，及函数指针。包含大量的指针相互转化。仅供参考。