by kirupa |
In the real world, you categorize and sub-categorize your
environment based on the objects that can be found in it.
For example, you have a chair which can be categorized as
furniture. Your refrigerator can be categorized as an
appliance. There are many such examples where a specific
object is classified by a more general category.
it comes to writing code, you can represent things as
objects also. This style of programming is known object oriented programming
(OOP) where we extend our idea
of objects from the real world and represent them using
In this tutorial, I will provide you with an introduction to
OOP by covering classes in C# and some of the interesting
things to be on the lookout out for. Since this will be a
long (but fun!) tutorial, I have divided the content into
the following smaller sections for easier digestion:
- Introducing Classes and Objects
- Setting Up your Project
- Defining a Class
- Public and Private Modifiers
- Methods (Functions)
- Instance Methods
- Static Methods
- AutoComplete in Visual Studio
Let's step away from the world of computers and think
about how objects and classes relate to the real world, and
since I am a big fan of outer space, I will use an
intergalactic theme throughout this tutorial.
In our solar system, you have planets. For something to
be a planet, it must meet the following criteria:
- Orbits around the sun.
- Has enough mass to maintain a stable shape.
- Does not shine with its own light.
There are a few more criteria, but you get the basic idea
of what characteristics something must possess in order to
be considered a planet. Now that you know what constitute a
planet represents, you can then associate real world things
that would fall under the planet category. There are a
handful of planets in our solar system, and one such planet,
Earth, is a pretty important one! The reason Earth and the
rest are considered planets is because they orbit the sun,
have mass, and do not produce their own light.
Ok, now let's link the planet example to our goal of
understanding classes. A class
would be similar to the definition of planets, for
classes set the guidelines and specify the
characteristics necessary for something to be associated
with it. The individual planets themselves - Mercury, Mars,
Earth, etc. - would be considered objects
because they inherit their unique characteristics from a
class called planet. Another way
of saying it would be that these objects are of
To recap, in order for something to be a planet, it must
posses all the characteristics as defined by your Planet
category. In order for an object to be part of a class, the
object must incorporate all of the characteristics specified
as being associated with the class. There are more
nitpicky details, but for now, we'll play it by ear and
learn those details along the way.
Onwards to the