Create a housing application for a property manager. Include a base class
named Housing. Include data characteristics such as address and year built.
Include a virtual method that returns the total projected rental amount.
Define an interface named IUnits that has a method that returns the
number of units. The MultiUnit class should implement this interface.
Create subclasses of MultiUnit and SingleFamily. SingleFamily
should include characteristics such as size in square feet and availability of
garage. MultiUnit might include characteristics such as the number of
units. Create .DLL components for the housing classes. Define a presentation
class to test your design.