A developer is hired to work on a special calculator software. The software should be running on Windows, Mac OS as well as Linux. The purpose of the calculator is to calculate tax return for all...

A developer is hired to work on a special calculator software. The software should be running on Windows, Mac OS as well as Linux. The purpose of the calculator is to calculate tax return for all employees in a company. However, the company has different categories of employees: Director, Manager and Worker whom requires different calculation models. Also, one employee belongs to only one category. Identify functional requirements for the software and draw its class diagram.