该文件是《软件工程》的课程设计。

我设计的是一个用java编写的计算器。

这个文件是计算机的软件设计模型，含有用例模型，分析类图，领域模型，设计模型，事务包，时序图等多个模块-The file is a " software engineering"　course design. I designed is a java prepared by the calculator. This file is a computer software design model, comprising a plurality of modules use case model, analysis class diagram, domain model, design model, transaction package, timing diagrams, etc.