Abstract Class in C#

What is an Abstract class in C#?

1.It is special kind of class that has implementation, we cannot instantiated(object).
2.It is the base class of derived class and it give functionality to derived or sub class.
3.Without Implementation of method is seem to be like an Interface but it doesn't support Multiple        Inheritance.

4.It can have both (Abstract method and  non Abstract method).
  ex:-   public abstract void sample();  // Abstract Method
           public void  sample(){//---} //Non Abstract Method with Implementation.


Program

> Abstract class with non Abstract Method;

using System;
using System.Text;
namespace Test_Application
{
    abstract class Vehicle
    {
        public void Car()
        {
            Console.WriteLine("Car is four wheeler");        
        }
    }
    class Program : Vehicle
    {    
        public static void Main(string[] args)
        {
            Program v = new Program(); //
            v.Car();
            Console.ReadLine();        
        }      
    }    
 }
  Output :-  Car is four wheeler

Note :- Here  we cannot create Vehicle as object  instead of  Program because it will show compilation error .

 Vehicle p = new Vehicle  =>   Program v = new Program();
           

>Abstract class  with  an Abstract Method.


using System;
using System.Text;


namespace Test_Application
{
    abstract class Vehicle
    {
       public abstract void Bicycle();    
    }
    class Program : Vehicle
    {
        public override void Bicycle()
        {
            Console.WriteLine("Bicycle is Two wheeler");
        }
        public static void Main(string[] args)
        {
            Program v = new Program();
            v.Bicycle();
            Console.ReadLine();        
        }      
    }    
 }

Output:-  Bicycle is Two wheeler

Note : While create an Abstract Method in abstract class :-
 
      1      abstract void  Bicycle();  // compilation error  because this considered as private
                                                        virtual or abstract member cannot be  private.

      2     public abstract void Bicycle(); // Is considered.

   
      3    In derived class =>  public override void Bicycle(){ ----};
            override keyword must required.


> Abstract class with Abstract Method and non Abstract Menthod;


using System;
using System.Text;


namespace Test_Application
{
    abstract class Vehicle
    {
        public void Car()
        {
            Console.WriteLine("Car is a four wheeler");
        }
       public abstract void Bicycle();    
    }
    class Program : Vehicle
    {
        public override void Bicycle()
        {
            Console.WriteLine("Bicycle is a Two wheeler");
        }
        public static void Main(string[] args)
        {
            Program v = new Program();
            v.Car();
            v.Bicycle();
            Console.ReadLine();        
        }      
    }    
 }


Output:-  Car is a four wheeler
                Bicycle is a Two wheeler

Author : praneet kumar

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