Set - 10

Question 11 :

What is the difference between an interface and abstract class?

Answer :

In the interface all methods must be abstract; in the abstract class some methods can be concrete. In the interface no accessibility modifiers are allowed, which is ok in abstract classes. 


Question 12 :

What is an abstract class?

Answer :

A class that cannot be instantiated. A concept in C++ known as pure virtual method. A class that must be inherited and have the methods over-ridden. Essentially, it is a blueprint for a class without any implementation. 
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Question 13 :

Does C# support multiple-inheritance?

Answer :

No.


Question 14 :

Who is a protected class-level variable available to?

Answer :

It is available to any sub-class (a class inheriting this class).


Question 15 :

Can you store multiple data types in System.Array? 

Answer :

No.