数据结构一双链表

typedef struct DLnode{
    int data;
    struct DLnode *next;
    struct DLnode *prior;//前驱指针
}DLnode,*DLinklsit;

//初始化链表
int InitDLilnlist(DLinklsit &L)
{
    L = new DLnode;
    if(L ==NULL)
    {
        return 0;//内存不足，分配失败
    }
    L->next = nullptr;
    L->prior = nullptr;
    return 1;
}

//判断链表是否为空
bool IsEmptyDLinklist(DLinklsit &L)
{
    if(L->next == nullptr)
    {
        cout<<"链表为空"<<endl;
        return true;
        
    }
    else
    {
        return false;
    }
}

//在p结点之后插入s结点
int InsertNextDLnode(DLnode *p,DLnode *s)
{
    if(p == NULL || s == NULL)
    {
        return 0;
    }
    s->next = p->next;
    if(p->next !=NULL)
    {
        p->next->prior = s;
    }
    s->prior = p;
    p->next = s;
    return 1;
}

//删除p结点后的q结点
int DeleteNextDLnode(DLnode *p)
{
    if(p == NULL)
    {
        cout<<"无后继结点"<<endl;
        return 0;
    }
    DLnode *q = p->next;//找到p的后继结点
    if(q == NULL)
    {
        cout<<"无后继结点"<<endl;
        return 0;
    }
    q->next = p->next;
    q->next->prior = p;
    delete q;
    return 1;
}