After you have an understanding of the structure of an object-oriented program, the rest is pretty much just filling in the blanks. Now you can quickly go through each of the basic elements of a C# program.
I have discussed a little bit about an abstract class. You can use the abstract modifier to declare an abstract method or property. An abstract class has the following properties:
An abstract class cannot be instantiated.
A non-abstract class that is derived from an abstract class must implement all of the abstract methods and properties.
An abstract class must provide implementations for all of the methods of an inherited interface.
An abstract class can declare its “implementation” of an interface method ...