Introduction of Object Oriented Programming Concept.

1. Md. Al-Imran
Lecturer
Department of Computer Science & Engineering
Dhaka International University
Bangladesh

2. 
 Define OOP
 OOP Vs. Structured Programming
 Main principle of OOP
 Encapsulation
 Abstraction
 Inheritance
 Polymorphism
 Overview
Contents

3.  Object-oriented programming is a method of
implementation in which programs are organized as
cooperative collections of objects, each of which
represents an instance of some class, and whose classes
are all members of one or more hierarchy of classes united
via inheritance relationships.
What is OOP ?

4. 
Structure Programming Object Oriented Programming
Top to Bottom Design Object focused design
Structure determines execution flow Conversion determines execution flow.
Moderately complex program Very Complex Program
Less data security More security
Less flexible More flexible
Less reusability More reusability
Less abstraction More abstraction
Structure Programming Vs. OOP

5. 
Reusability
Platform Independent
Security
Client/Sever Application
Graphical User Interface
Design Pattern
Portability (WORA)
Why Java?

6. 
 Write Ones Run Anywhere
WORA

7. 
 Fundamental Principles of Object Oriented Programming:
1. Encapsulation.
2. Abstraction.
3. Inheritance.
4. Polymorphism.
Main principle of OOP

8. 
 Encapsulation is the mechanism that binds together
code and the data it manipulates, and keeps both
safe from outside interference and misuse.
Encapsulation

9. 
i. Protection
ii. Consistency
iii. Allows change
Advantages of Encapsulation

10.  abstraction is a process of hiding the implementation
details from the user, only the functionality will be
provided to the user. In other words, the user will have the
information on what the object does instead of how it
does.
 In Java, abstraction is achieved using Abstract classes and
interfaces.
Abstraction

11. 
 An abstract class is a class that is declared with abstract keyword.
 An abstract method is a method that is declared without an
implementation.
 An abstract class may or may not have all abstract methods. Some
of them can be concrete methods.
 A method defined abstract must always be redefined in the subclass,
 Any class that contains one or more abstract methods must also be
declared with abstract keyword.
 There can be no object of an abstract class. That is, an abstract class
can not be directly instantiated with the new operator.
Abstract Class Vs. Abstract
Method

12. 
 Inheritance is the process by which one object acquires the properties
of another object.
 A class that is derived from another class is called a subclass(also a
derived class, extended class, or child class).
 The class from which the subclass is derived is called a super class
(also a base class or a parent class).
Inheritance

13. 
 The sub-class inherits the base class’ data members and member
functions.
 A sub-class has all data members of its base-class plus its own.
 A sub-class has all member functions of its base class (with changes)
plus its own.
Cont’d

14. 
Inheritance has a lot of benefits
 Extensibility
 Reusability
 Provides abstraction
 Eliminates redundant code
 Use inheritance for building a relationships
E.g. dog is--a animal (dogs are kind of animals)
Benefits of Inheritance

15.  Polymorphisms comes from Greek word that means 'many forms'.
 More precisely Polymorphisms means the ability to request that
the same methods be performed by a wide range of different types
of things.
Polymorphism

16. 
 It is achieved by using many different techniques named
method overloading and method overriding.
Cont’d

17. 
 Discuss about OOP.
 Differentiate Structure Programming and OOP.
 Main principles of OOP.
 Encapsulation.
 Abstraction.
 Inheritance.
 Polymorphism.
Overview