How to create Abstract class in C#.

Abstract class 
class :- 1)Concreet class(We can create object  of that)
	**method:- concreet method(method having body)
2)Abstract class(we can not create object, because it is too general )
	**method :-1) abstract method(method without body)
		  2) concrete method it is used to inherit

Code:

abstract class human
{
	//Abstract methods
	public  abstract void hair();
	//Concrete method
	public void display()
	{
		System.Console.WriteLine("hello");
	}
	
	
}
class boys : human
{
	public override void hair()
	{
		System.Console.WriteLine("Small");
	}
	
}
class girls : human
{
	public override void hair()
	{
		System.Console.WriteLine("LONG");
	}
}
class  a
{
	public static void Main()
	{
		boys b=new boys();
		girls g=new girls();
		b.hair();
		g.hair();
		b.display();
		g.display();
		
		
		
	}
}