编辑代码

#include <stdio.h>
#include<stdlib.h>
#include<stdbool.h>
//双链表定义
typedef struct DNode
{
    int data;
    struct DNode *prior;
    struct DNode *next;
}DNode,*DLinkedList;
//初始化双链表
bool InitList(DLinkedList *L)
{
    //头结点分配空间
    (*L)=(DNode*)malloc(sizeof(DNode));
    if((*L)==NULL)
        return false;
    (*L)->next=NULL;
    (*L)->prior=NULL;
    return true;
}
//按照位序插入数据
bool ListInsert(DLinkedList *L,int i ,int e)
{
    if(i<1)
        return false;
    int j=0;
    DNode *p = *L, *s;
    while(p!=NULL&&j<i-1)
    {
        p=p->next;
        j++;
    }
    if(p==NULL)
        return false; //前驱结点为空，i输入错误
    s=(DNode*)malloc(sizeof(DNode));
    s->data=e;
    s->next=p->next;
    if(p->next!=NULL)
       p->next->prior=s;
    s->prior=p;
    p->next=s;
    return true;
}
//在p结点后插入新结点
bool InsertNextNode(DNode* p,int e)
{
    if(p==NULL)
        return false;
    DNode *s=(DNode*)malloc(sizeof(DNode));
    s->data=e;
    s->next=p->next;
    s->prior=p;
    if(p->next!=NULL)
        p->next->prior=s;
    p->next=s;
    return true;
}
//删除p结点的后继结点
bool ListDelete(DNode *p)
{
    if(p==NULL)
        return false;
    if(p->next==NULL)
        return false;
    DNode* s = p->next;
    if(s->next!=NULL)
        s->next->prior=p;
    p->next=s->next;
    free(s);
    return true;
}
bool DestoryList(DLinkedList *L)
{
    while((*L)->next!=NULL)
        ListDelete(*L);
    // DNode *p=*L;
    // while(p->next!=NULL)
    // {   DNode *temp = p->next;
    //     ListDelete(p);
    //     p=temp;
    // }
    free(*L);
    *L=NULL;
    return true;
}
//打印链表
void PrintList(DLinkedList L)
{   
    if(L->next==NULL)
        printf("链表已空");
    DNode *p=L->next;
    while(p!=NULL)
    {
        printf("%d ",p->data);
        p=p->next;
    }
    printf("\n");
}
//按照位序获取结点
DNode* GetNode(DLinkedList L,int i)
{
    if(i<1)
        return false;
    int j=0;
    DNode *p=L;
    while(p!=NULL&&j<i)
    {
        p=p->next;
        j++;
    }
     return p;
}
int main () 
{
    DLinkedList L;
    InitList(&L);
    
    ListInsert(&L,1,1);
   InsertNextNode(L,10);
    ListInsert(&L,2,2);
    ListInsert(&L,3,3);
     
    PrintList(L);
    printf("%d \n",GetNode(L,3)->data);
    ListDelete(GetNode(L,3));
    PrintList(L);
    DestoryList(&L);
    PrintList(L);
}