为三种不同职业的人设计合理的类型，每种职业的人都定义一个类型来描述。定义一个抽象作为所有这些人的基类，在其中定义一个纯虚拟函数作为所有人显示职业身份的功能接口。-Rational design of three different career types, each occupation to define a type described. Define an abstract base class for all these people, in which the definition of a pure virtual function professional identity as all functional interfaces.