#include <stdio.h>
#include <stdlib.h>
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);
}