Basic Concepts of Object Oriented Programming (OOP) explained in layman's terms. For having a better understanding of building blocks of OOPs Language. Explanantion of Class, Objects & Methods followed by explanation of Message Passing, Inheritance, Abstraction, Encapsulation, & Polymorphism with examples.

1. Object Oriented
Programming
Concepts
By,
ABHIGYAN SINGH YADAV (10/ICS/003)

2. Object Oriented Programming
• An object oriented program may be
considered a collection of
interacting objects.
• Where each object is capable of
sending and receiving messages and
processing data.

3. Example

4. Classes, Objects & Methods
• Class is a family of objects with
similar variable components and
methods
• A class defines characteristics (i.e.
attributes and behaviour) of an
object.

5. Class Example
Car
Year
Make
Model
ON/OFF
Gear
Accelerate
Decelerate
ATTRIBUTES
BEHAVIOUR

6. Object, Classes & Method
• Object are entities that encapsulate
data & related operations.
In simple words,
• Object is something that can
occupy memory & has a
(modifiable) state.
• It is an instance of a class.

7. Object Example
Object Name Class Name

8. Object, Classes & Method
• Method is a behaviour of an
object.
• Within a program method
usually affects only one object.

9. Object Example
Object Name Class Name

10. Basic Concepts Of OOP
• Message Passing
• Inheritance
• Abstraction
• Encapsulation
• Polymorphism

11. Message Passing
• This is the process where an object
sends data to another object or asks
the object to invoke a method.
• The objects communicate with one
another by sending and receiving
information much the same way as
people pass message to one
another.

12. Message Passing
• Message Passing makes it easier
to talk about building systems
that directly model real world
counterparts.

13. Example
MESSAGE:
Accelerate
John: Driver
PushGas() {
My
Ferrari.accelerate()
}
My Ferrari: CAR
{
Accelerate()
}

14. Inheritance
• Inheritance is the process by
which objects of one class
acquire the properties of object
of another class.
• Inheritance provides the idea of
reusability.

15. Example
Parent Class, Base Class
or Super Class
Derived Class,
Sub Class, Child
Class
• A sub class can alter its
inherited attributes or
methods
• A sub class can also
include its own attributes
& behaviour.

16. Abstraction
• Abstraction is the act of
representing essential features
without including the
background details or
explanation.

17. Example
MESSAGE:
Accelerate
My Ferrari: CAR
{
Accelerate()
}
Accelerate()
{pump fuel, Mix
with air, ignite,
…pressure
created,… moves
pistons…….}

18. Encapsulation
• Encapsulation is the technique of
packaging thing together so as
to form a well defined
programming unit.
• The wrapping up of data &
methods into single unit (called
class) is known as Encapsulation.

19. Encapsulation
• It also protects the integrity of an
object by preventing programs
from changing internal data of
an object into something invalid.
• This insulation of the data from
direct access by the program is
called data hiding.

20. Polymorphism
• Polymorphism means the ability
to take more than one form.
• i.e. an operation or method may
exhibit different behaviour in
different instances.

21. Example
• Consider the method
brake for the three
objects of class car.
• The method break
will perform best in
F1 Racer, good in
sedan & average in
wagon.
• i.e. Break method
will have different
form for the
different objects.

22. Advantages of OOP
• We can eliminate redundant code.
• We can extend use of existing
classes
• Data hiding helps in making secure
programs
• Object oriented system can be
easily upgraded from small to large
systems.

23. Application of OOP
• Real-time systems
• Simulation and modelling
• Object-oriented databases
• Hypertext, hypermedia and
expertext and
• CAD system etc.