//struct#include <stdio.h>#include <stdlib.h>#include <string.h>/**********************双向链表************************************/typedef struct Student_Double{    char name[10];    int  point;    struct Student_Double *preStu;    struct Student_Double *nextStu;} StudentDouble;//创建双向链表StudentDouble *CreateDoubleLinkTable(void){    int i = 0;    StudentDouble *head = NULL;    head = (StudentDouble *)malloc(sizeof(StudentDouble));    head->name[0]=‘\0‘;    head->point = 0;    head->preStu = NULL;    head->nextStu = NULL;        StudentDouble *temp,*currentNode;    currentNode=head;    while (i<=9) {        temp = (StudentDouble *)malloc(sizeof(StudentDouble));        strncpy(temp->name,"Node",sizeof(temp->name));        temp->point = i;        temp->preStu = currentNode;        temp->nextStu = NULL;                currentNode->nextStu = temp;                currentNode = temp;        i++;    }        return head;}//正序查询StudentDouble * SelectDoubleLinkTableFormHead(StudentDouble *head){    StudentDouble *endNode = NULL;    StudentDouble *next = head->nextStu;    if (next == NULL) {        printf("查询失败,不是链式结构\n");        exit(0);    }        int i =0;    while (next) {        printf("index %d; studentName is %s;  point is %d\n",i+1,next->name,next->point);        if (next->nextStu == NULL) {            endNode = next;            printf("双向链表尾节点：%d \n",endNode->point);        }        next=next->nextStu;        i++;    }    return endNode;}//反序查询void SelectDoubleLinkTableFormEnd(StudentDouble *end){     StudentDouble *pre = end->preStu;    if (pre==NULL) {        printf("查询失败,不是链式结构\n");        exit(0);    }    pre = end;    int i = 0;    while (pre) {        if (pre->name[0]==‘\0‘) {            //头链            break;        }        printf("index %d; studentName is %s;  point is %d\n",i+1,pre->name,pre->point);        pre = pre->preStu;        i++;    }}//双向链表 插入节点  上一节点序号|插入节点名StudentDouble *insertStudentDoubleLinkTable(StudentDouble *head,char *content){    if (!content) {        exit(0);    }    //分割字符串    char *token;    char nodeName[10];    int  nodeIndex;    token = strtok(content,"|");    int i = 0;    while (token != NULL) {        if (i>0) {            strncpy(nodeName,token,sizeof(char[10]));        }else{            nodeIndex = atoi(token);        }        token = strtok(NULL,"|");        i++;    }        //查找节点    StudentDouble *next = head->nextStu;    if (next==NULL) {        printf("不是链式结构");        exit(0);    }    int search = 0;    StudentDouble *searchNode = NULL;    while (next) {        if (next->point == nodeIndex) {            search = 1;            searchNode = next;        }        next = next->nextStu;    }    if (search==0) {        printf("没有找到节点序号为%d 的节点",nodeIndex);        exit(0);    }    //插入节点    StudentDouble *nextLinkTable = searchNode->nextStu;    //创建新节点    StudentDouble *new = (StudentDouble *)malloc(sizeof(StudentDouble));    strncpy(new->name,nodeName,sizeof(new->name));    new->point = 100;//这两随机去的数。    new->preStu = searchNode;    new->nextStu = nextLinkTable;        searchNode->nextStu = new;        return head;}//双向链表  删除节点StudentDouble *DelegateDoubleLinkTable(StudentDouble *head,int nodeIndex){    //查找节点    StudentDouble *next = head->nextStu;    if (next==NULL) {        printf("不是链式结构");        exit(0);    }    int search = 0;    StudentDouble *searchNode = NULL;    while (next) {        if (next->point == nodeIndex) {            search = 1;            searchNode = next;        }        next = next->nextStu;    }    if (search==0) {        printf("没有找到节点序号为%d 的节点",nodeIndex);        exit(0);    }    StudentDouble *preNode = searchNode->preStu;    StudentDouble *nextNode = searchNode->nextStu;        preNode->nextStu = nextNode;    nextNode->preStu = preNode;        //释放    free(searchNode);    return head;}int main(void){    char sf[15];    int num; /**     *  创建双向循环链表     */    StudentDouble *head = NULL;    StudentDouble *end = NULL;    printf("开始创建双向链表Y|N \n");    scanf("%s",sf);    if (strcmp(sf,"Y")==0) {       head = CreateDoubleLinkTable();    }    printf("正序查询双向链表Y|N \n");    scanf("%s",sf);    if (strcmp(sf,"Y")==0) {      end = SelectDoubleLinkTableFormHead(head);    }        printf("反序查询双向链表Y|N \n");    scanf("%s",sf);    if (strcmp(sf,"Y")==0) {        printf("双向链表尾节点：%d \n",end->point);        if (end->point == 9) {            printf("双向链表反向查询\n");            SelectDoubleLinkTableFormEnd(end);        }    }        printf("插入双向链表 如：4(上一个节点序号)|name(要插入的节点名)\n");    scanf("%s",sf);    head = insertStudentDoubleLinkTable(head,sf);    SelectDoubleLinkTableFormHead(head);        printf("删除双向链表节点 输入要删除节点序号\n");    scanf("%d",&num);    head = DelegateDoubleLinkTable(head,num);    SelectDoubleLinkTableFormHead(head);    return 0;}