1 循环双链表后插

bool InsertNextDNode(DNode *P, DNode *s){
    s->next = p->next;                      //将结点*s插入到结点*p之后
    p->next->prior = s;
    s->prior = p;
    p->next = s;
    return ture;
}

2 循环双链表后删

bool DeleteNextDNode(DNode *p){
    DNode *q = p;
    p->next = q->next;
    q->next->prior = p;
    free(q);
    return ture;
}