Abstract class without any abstract method

Question

I am surprised to know that an abstract class in C# is possible with no abstract methods also.

abstract class AbstractDemo
{
 public void show()
  {
    Console.WriteLine("In Show Method"); 
   }
}
class MainDemo:AbstractDemo
{
 public static void Main()
 {
    Console.WriteLine("In Main Method");
 }
}

Any explaination ?

Answer 1

Sometimes you don't want to give the possibility to instantiate a class but you need this class as a base class for other classes.

The reason for choosing abstract classes over interfaces is that you can provide some basic implementation.