1-1 Oop Concept

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Introduction To OOP1.0

Fundamentals Of JavaProgramming Language2.0

Exception Handling3.0 Classes, Inheritance And

Polymorphism4.0

2012 | PN ROZITA SAAD1


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2


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Define OOP1

Describe the History Of OOP

2 List the Advantages Of Using OOP3

Illustrate the Basic Terminologies Of OOP4 Distinguish between Abstraction &

Encapsulation5 Differentiate between Structured

Programming & OOP Approach6



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According to Wikipedia, Object Oriented Programming (OOP) is a programmingtechnique that uses objects to design the applications and computer programs.

It also can be define as a type of programming where the programmer can define datatypes and types of operations, which will be performed on the data structure.

Example:

Data data types

Data Structu re Student No. Integer

Mark float

Types of o perat ion:Student No. :

Sort student list based on

Student No.

Mark :

Calculate mark.



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By using this method, data structure will become an object such as Student object,

which consists of data and functions.

The programmer can create relationship between one object with another object such

as an object inherits characteristics from another object

Object-oriented programming is a method used to write programs where data and

behaviours are packaged together in one class. Object is a member of a class.



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In the 1960s, Simula language were developed by Norwegian Computing Center.

It became the first OOP language which applies the OOP concepts.

It was designed for the purpose of creating simulations, and was developed by Kristen

Nygaard and Ole-Johan Dahl in Norway.

In the 1970s, Alan Kay developed Smalltalk language at Xerox Parc (Palo Alto

Research Center).

Targeted to be understandable to people with no prior training in computer use.

Demonstrated by experiments conducted using children as programmers

In the 1980s, Bjarne Stroustrup at Bell Lab who had learned Simula during his PHDstudies develop C++ as an extension of C.

Later many other OOP languages were developed: Eiffel, Objective-C, Actor,Object

Pascal and etc.



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Code extensibility / kod boleh ditambah

Ability to add codes, which are already existing and consistent with needs.

Code reusability / kod boleh diguna berulangkali Existing code can be tested first before it is inherited from previous module.

This will save cost and time needed to develop software.

With this method, it will help to increase programmers productivity.



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Represent real world / menggambarkan dunia sebenar

Using object-oriented concept, it will assist the programmer in creating a module because

data used represents real situations.

Data security / keselamatan data

The use of encapsulation concept has made data to be protected from misuse by an

unauthorized person.



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1. Object

Object is the term used to explain many things.

Example: student, chair and circle. An Object consists of data and method

Properties of an object are called data. In the real world, characteristics of an object can be

divided into two types:

Data that can be seen such as a human with two hands.

Data that cannot be seen such as a human with a name.

Method is a set of function that manipulates data, such as method DetermineStatus() candetermine exam result for object student.


Object : Student

Data : name, address, icno, sid, marks, status

Method : DetermineStatus()


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2. Class A set of objects that have similar attributes(characteristics, which can be seen.) and methods.

Attributes and methods of a class can be used by each object from that class.


class Student

{ String name, address, status;int icno, sid;

double marks;

char DetermineStatus()

{ if marks >= 40

status = Pass;

else

status = Fail;

}

} Class

Example 1 : Definition of Class Student

data

method

Example 2 : Definition of Class Box

class Box

{ double width, height, depth;

double ComputeVolume()

{ return( width * height * depth ); }

double ComputeArea()

{ return( width * height ); }

}

data

method

Class


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3. Encapsulation Encapsulation is a process of tying together all data and methods that form a class and

control the access to data by hiding its information.

It enables access to object just by using methods of that object.

It is one of the security features in object-oriented programming (OOP).



Class Student

Name, Student ID, Address,

IC No

Calculate_result()

Determine_grade()

Print_result()

Figure above Explains the concept of encapsulation in OOP for class Student

Based from the example given, data and methods are combined in one class. If the college management wants to

get the status whether a student pass or fail, they only have to know the status without knowing how to

determine or calculate the grade. So, this is a way of implementing encapsulation where the code in the program

is hidden thus to prevent from being modified.


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4. Data Abstraction Data abstraction is a process to delete all unnecessary attributes and remain the necessary

attributes to describe an object



StudentObject

AbstractionName, Student ID,

Address, IC No

Attribute

Calculate_mark (),Determine_grsde (),

Print_result ()

Behaviors

Student Class

Figure Explain about abstraction

concept


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5. Inheritance Create a new class from an existing class together with new attributes and behaviours.

The new class will have the same ability as the base class.

Use the concept of code reusability.


Class A

Class B

Class C

Base class to class B

Derived class to class A

Base class to C, D and E

Derived class to class B

Class EClass D

Figure : Relationship between one class with

another class. Derived class can be inherits

characteristic from a base class.


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6. Polymorphism Polymorphism is a process of giving the same message to two or more different objects and

produce different behaviours depending on how the objects receive the message.

It is said to be One interface, many methods.


Example 1:Message: Withdraw a money from bank

Action Object

Student1 : Using ATM machine from Bank account.

Student2 : Using ATM Machine from other Bank (MEPS)


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Abstraction Encapsulation

Delete all unnecessary data and remainthe necessary data only

control the access to data by hiding its

information



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Structured Programming Object Oriented Programming

1 Based on programmer definition functionSplit a big program to several functions. Each

function will perform the task more specific.

Object Oriented Programming Technique

The use of encapsulation concept

combined data and function in one

component ( class).

2 Program code cannot be reused

Each function assign to do specific task only.

We must accept the function as it is. Tomodify it, the code need to copy and modify it

based on it requirement

Allowed code reusability

It can be done through inheritance

technique. This technique allowed object toinherits characteristic (function and data)

other object.


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3 Data manipulation function

Data will be send to specific function to be

manipulate where the function is notdetermine first.

Using encapsulation to react on data

Encapsulation is used to package data with

function that will take an action over the data.It define which function will be perform to each

object. Class will control any operation done to

data and function inside it.

4 No data control access.

Main function will access all data and

function in the program.

Restriction in retrieving data.

Access control exist for each data in the

class.

5 Not supported polymorphism

Each data must be declared before do

any operation on it.

Used polymorphism

Allowed one function to be executed with

various method.

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1-1 Oop Concept