C# program,

Abstract classes and Interfaces

• Create an abstract class Product with following
  • Properties Price (Decimal), Code (string), Description (string)
• Create an interface ISellable with the following
  • Method sell that takes the count of the products to sell and returns the cost

public decimal sell(int count);

• Create a concrete class Book that
  • Inherits from class Product
  • and implements interface ISellable
  • Has additional Property Author (string)
  • Add a constructor with parameters, and ToString method to display all of data of class Book
• Similarly, create anot concrete class Software that
  • Inherits from class Product
  • and implements interface ISellable
  • Has additional Property Version (string)
  • Add a constructor with parameters, and ToString method to display all of data of the class Software
• Finally, write a client code (main program) that will utilize the class and interface hierarchy you created.
  • Create two Book objects for the following books
    • C# 8.0 in a Nutshell, with price $50.99 and with ISBN 978-1492051138 by Jack Smith
    • C#: Advanced Features and Programming Techniques, with price $2.99 and with ISBN 100-1492051000 by Jill Smith
    • Ask the user how many of each book the user wants to buy and then display a report of how much the total cost is.
  • Create a Software object for the following Software
    • Microsoft 365 Personal with price $69.99 and version 16.0.10827
    • Ask the user how many of the Microsoft 365 the user wants to buy and then display a report of how much the total cost is.