1 Oop Concepts

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Introduction To OOP1.0

Classes And Objects2.0

Inheritance and Polymorphism3.0

Exception handling4.0

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2009 | PN NORHASLIZA BT MUHAMAD NOR


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Define OOP1

History Of OOP2

Advantages Of Using OOP3

Basic Terminologies Of OOP4

Abstraction & Encapsulation5

Structured & OOP Approach6

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A type of programming where the programmer can define data types and types ofoperations, which will be performed on the data structure.

Example:Data data types

Data Structure Student No. Integer

Mark float

Types of operation:

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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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() can

determine exam result for object student.

Objek : Pelajar

Data : nama, alamat, nokadpengenalan, sid,

markah, statusMethod: MenentukanStatus()



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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;

}

} Kelas

Contoh 1 : Mendefinisikan Kelas Pelajar

data

method

Contoh 2 : Mendefinisikan Kelas Kotak

class Box

{ double width, height, depth;

double ComputeVolume()

{ return( width * height * depth ); }

double ComputeArea()

{ return( width * height ); }

}

data

method

Kelas



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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


Objek Pelajar

PengabstrakanNama, ID pelajar,

Alamat, No KP

Sifat/(Attribute)

Kira_markah (),Tentu_gred (),

Cetak_keputusan ()

Kelakuan/ (Behaviors)

Kelas Pelajar

Rajah Menerangkan mengenai konsep

pengabstrakan


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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

Kelas asas (base class)

kepada B

Kelas terbitan (derived class)

kepada A

Kelas asas kepada C, D and E

Kelas terbitan kepada B

Class EClass D

Rajah : Hubungan di antara satu kelas dengan

kelas lain. Kelas terbitan boleh

mewarisi ciri-ciri Kelas asas.


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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.

Contoh 1:Mesej: Keluarkan wang anda dari bank:

Objek TindakanPelajar 1 : Menggunakan mesin ATM yang disediakan oleh pihak

bank di mana akaun dibuka

Pelajar 2 : Menggunakan mesin ATM (MEPS) dari bank lain


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Pengaturcaraan BerstrukturPengaturcaraan Berorientasikan Objek

1 Berasaskan Fungsi Yang didefinisikanPengaturcaraMemecahkan satu program yang besar pada

beberapa fungsi. Setiap fungsi akan

melaksanakan tugas yang lebih spesifikContoh:

void main( ){

..Peribadi (nama,umur);}void Peribadi(char *a, int b){ //Definisi fungsi DataPeribadi

}

Teknik Pengaturcaraan Berasaskan Objek

Penggunaan konsep pengkapsulan yang

menggabungkan data dan fungsi dalam

satu komponen (kelas)

Contoh:

class Individu{.. // datavoid DataPeribadi( )};main( ){

Individu a;/*Objek a capai data dan method

dari

kelas Individu*/}


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2 Kod aturcara tidak boleh digunakanberulangkali

Setiap fungsi ditugaskan untuk satu tugas

yang spesifik. Kita mesti menerima fungsi

itu sebagaimana ia ditulis.

Untuk mengubahsuainya, kod itu haruslah

disalin semula dan diubah untuk

memenuhi keperluan.

Contoh:Kita telah merekacipta satu radio untuk

kegunaan rumah.

Teknologi yang digunakan itu boleh

digunakan untuk mencipta radio kereta

ataupun radio yang digunakan di tepi

pantai.

Membenarkan penggunaan kod yangberulang kali

Ia boleh dilakukan melalui teknik pewarisan.

Teknik ini membolehkan objek untuk mewarisi

ciri-ciri (fungsi dan data) objek lain.

Contoh:Kita menggunakan radio kegunaan rumah

yang telah dicipta untuk digunakan pada

kereta dan di pantai

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3 Fungsi Memanipulasikan Data

Data (cth: nama, umur) akan dihantar ke

fungsi-fungsi tertentu (cth: cetak, papar,tambah, dan padam) untuk

dimanipulasikan. Fungsi yang akan

memanipulasikan data tidak ditetapkan

terlebih dahulu.

Menggunakan Pengkapsulan Untuk Bertindak

Ke atas Data

Pengkapsulan digunakan untuk mempakejdata bersama fungsi yang akan bertindak ke

atas data. Ia mengenalpasti fungsi yang akan

dilaksanakan ke atas setiap objek. Kelas akan

mengawal sebarang operasi keatas data dan

fungsi yang berada didalamnya.


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4 Tiada Kawalan Capaian Data

Fungsi main ( ) boleh capai semua data

dan fungsi yang terdapat pada program

Kekangan Dalam Mencapai Data

Wujudnya kawalan capaian terhadap data di

dalam kelas. Contohnya katakunci private

dan protected. Untuk mencapai private data

ia mesti dilakukan melalui method ataupun

mekanisma pengkapsulan.

5 Tidak menyokong polimorfisma

Setiap data mesti diisytiharkan terlebih

dahulu sebelum operasi ke atasnya

dilaksanakan.

Penggunaan Polimorfisma (polymorphism)

Polimorfisma membolehkan satu fungsi

dilaksanakan dengan pelbagai kaedah.

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1 Oop Concepts