abstract:- abstract method can not declare any body and variables in abstract class and abstract method implemented in child class by override keyword . virtual:- we can can declares any body and variables in virtual method it can be also implemented method in child class using override keyword.

abstract:- abstract method can not declare any body and variables in abstract class and abstract method implemented in child class by override keyword . virtual:- we can can declares any body and variables in virtual method it can be also implemented method in child class using override keyword.

abstract:- abstract method can not declare any body and variables in abstract class and abstract method implemented in child class by override keyword . virtual:- we can can declares any body and variables in virtual method it can be also implemented method in child class using override keyword.

abstract:- abstract method can not declare any body and variables in abstract class and abstract method implemented in child class by override keyword . virtual:- we can can declares any body and variables in virtual method it can be also implemented method in child class using override keyword.

ewwe

ewwe

ewwe

ewwe

http://softwarecafeblog.blogspot.in/2011/05/abstract-vs-virtual-in-c.html

Please refer to the following URL to know the differences between Abstract Method and Virtual Method,http://onlydifferencefaqs.blogspot.in/2012/08/oops-difference-faqs-3.html

Virtual method has an implementation & provide the derived class with the option of overriding it. Abstract method does not provide an implementation & forces the derived class to override the method.

important Notes:

(a)Any Class with abstract method or property in it must be declared abstract

(b)Attempting to instantiate an object of an abstract class retults in a compilation error

Example:

Shape m_MyShape = new Shape(); //it is Wrong to that.

But we can do that.

Shape m_MyShape = new Circle(); // True

Or

Shape m_MyShape; /* declare refrences only, and the refrences can refer to intances of any concrete classes derived from abstract class */ Circle m_MyCircle = new Circle(); m_MyShape = m_MyCircle; // Also True

(d)An abstract class can have instance data and non-abstract methods -including constructors-.
Tutorial

Our Tutorial has 4 classes { Shape --> Point --> Cirlce --> Cylinder } Abstract Class Shape has 2 virtual methods Area() & Volume(), and one abstract property ShapeName

Class Point only override the inherited property ShapeName as point do not have any area or volume Also it has to properties X & Y (pntA[X,Y]) for example

Class Cirlce override method Area() & the property ShapeName and doen't override volume as it has no volume. Also Cirlce has some methods to provide its Diameter & Circumference which will be used by class Cylinder.

Class Cylinder override all methods in Class Shape, and use the service methods in Class Circle (Diameter & Circumference) to calculate the Area() & Volume(). Check the roject and it is well commented.