图书管理基本业务活动包括：对一本书的采编入库、清除库存、借阅和归还等等。试设 计一个图书管理系统，将上述业务活动借助于计算机系统完成。 要求： （1）每种书的登记内容至少包括书号、书名、著者、现存量和总库存量等五项。

（2）作为演示系统，不必使用文件，全部数据可以都在内存存放。要用 B-树（4 阶树） 对书号建立索引，以获得高效率。 （3）系统应有以下功能： 采编入库、清除库存、借阅、归还、显示（以凹入表的形式显示）等。-Library management basic business activities include: editing of a book storage, remove stock, borrow and return and so on. Try to design a library management system, the operations described above by means of a computer system to complete. Requirements: register content (1) of each book includes at least ISBN, title, author, and total inventory of existing other five.

(2) as a demonstration system, do not use a file, all the data can all be stored in memory. Use the B- tree (4 TREES) ISBN indexed to obtain high efficiency. (3) The system should have the following features: editing storage, clearing inventory, borrow, return, display (in the form of a concave of the table) and the like.