删除结点时delete 报错is_block_type_valid

delete报错is_block_type_valid

void book_delete(LinkList& L, int i)
{
    Lib_node* p = L;
    int cnt = 1;
    while (p->_next && cnt < i)
    {
        p = p->_next;
        ++cnt;
    }
    if (cnt != i)
    {
        cout << "Invalid" << endl;
        return;
    }
    if (!p->_next)
    {
        cout << "Invalid" << endl;
        return;
    }
    Lib_node* q = p->_next;
    p->_next = p->_next->_next;
    delete q;//报错
    q = NULL;
}//删除第i个结点

int main()
{
    LinkList L= new Lib_node;//L指向头结点
    int n;
    cin >> n;
    Lib_node* p = L;
    for (int ix = 0; ix < n; ++ix)
    {
        Lib_node* q=new Lib_node;
        cin >> *q;
        p->_next = q;
        p = q;
    }//创建链表
...
}

cin >> *q
你的结构重载>>操作符了？
没看到你调用上面的删除函数啊