C语言实现双向链表删除、插入、双向输出

#include<cstdio>#include<cstdlib>typedef struct DoubleLinkedList{    int data;    struct DoubleLinkedList *pre;    struct DoubleLinkedList *next;}DlinkedList_Node;//建立链表DlinkedList_Node* createDLink(){    DlinkedList_Node *head,*p,*s;    int x;    head = (DlinkedList_Node*)malloc(sizeof(DlinkedList_Node));    p = head;    while(1)    {        printf("please input the data: \n");        scanf("%d",&x);        if(x != 65535)        {            s = (DlinkedList_Node*)malloc(sizeof(DlinkedList_Node));            s ->data = x;            s-> pre = p;            p->next = s;            p=s;        }        else            {                printf("\n数据输入结束\n");                break;            }    }    p->next = NULL;    head = head ->next;    head->pre = NULL;    return head;}//顺序、反序打印链表void printDLink(DlinkedList_Node *head){    DlinkedList_Node *p,*s;    p = head;    printf("正序输出双向链表：\n");    while(p)    {        printf("%d ",p->data);        s = p;        p = p->next;    }    printf("\n 逆序输出双向链表: \n");    while(s)    {        printf("%d ",s->data);        s = s->pre;    }    printf("\n \n");}//删除一个结点DlinkedList_Node* deleteDlinkedList_Node(DlinkedList_Node *head,int i){    DlinkedList_Node *p;    p = head;    if(p->data == i)    {        head = p->next;        head->pre = NULL;        free(p);        return head;    }    while(p)    {        if(p->data == i)        {        p->pre->next = p->next;        p->next->pre = p->pre;        free(p);        return head;        }        p = p->next;    }    printf("没有找到想要删除的数据\n");    return head;}//插入一个结点DlinkedList_Node* insertDlinkedList_Node(DlinkedList_Node *head,int i){    DlinkedList_Node *p,*temp;    p = head;    temp = (DlinkedList_Node*)malloc(sizeof(DlinkedList_Node));    temp ->data = i;    if(i < p->data)//比头结点数据小，插入到链表头部    {        head = temp;        head->next = p;//此处p为原来的head        head->pre = NULL;        p->pre = head;//此处p为原来的head        return head;    }    while(p != NULL && i > p->data)//寻找合适的插入位置    {        p = p->next;    }    if(i < p->data)//在链表中间某处找到合适插入位置    {        temp ->next = p;        temp ->pre = p->pre;        p ->pre->next = temp;        p ->pre = temp;        return head;    }    else//没有找到合适的位置，只有将数据插入到链表尾部    {        p->next = temp;  //遍历到链表尾部，p==NULL        temp ->pre = p;        temp ->next = NULL;        return head;    }}int main(){    DlinkedList_Node *head;    head = createDLink();    printDLink(head);    head = insertDlinkedList_Node(head,1012);    head = deleteDlinkedList_Node(head,1991);    printDLink(head);}/*****************************运行结果如下：please input the data:1991please input the data:1992please input the data:2013please input the data:2014please input the data:512please input the data:420please input the data:65535数据输入结束正序输出双向链表：1991 1992 2013 2014 512 420 逆序输出双向链表:420 512 2014 2013 1992 1991正序输出双向链表：1012 1992 2013 2014 512 420 逆序输出双向链表:420 512 2014 2013 1992 1012