Create an application class named LetterDemo that instantiates objects of two classes named Letter and CertifiedLetter and that demonstrates all their methods.

Programming in C# Programming Exercises Create an application class named LetterDemo that instantiates objects of two classes named Letter and CertifiedLetter and that demonstrates all their methods. The classes are used by a company to keep track of letters they mail to clients. The Letter class includes auto-implemented properties for the name of the recipient […]