F 3031 Object Oriented Programming CHAPTER 1 INTRODUCTION

F 3031 Object Oriented Programming CHAPTER 1 INTRODUCTION TO OBJECT ORIENTED PROGRAMMING (OOP) By: PN. NOR ANISAH BINTI MOHD SAAD

1 Define OOP 2 History of OOP 3 Advantages of using OOP 4 Basic Terminologies of OOP 5 Abstraction and Encapsulation 6 Structured and OOP Approach

1 DEFINE OBJECT � An object can be considered as a "thing" that can perform a set of activities (behaviours). � For example, a "Student" object can tell you its name or its address.

DEFINE OBJECT � An object is a "black box" which receives and sends messages. � A black box actually contains code and data � Messages define the interface to the object. Everything an object can do is represented by its message interface. So you shouldn't have to know anything about what is in the black box in order to use it. � �

1 � In DEFINE OBJECT ORIENTED PROGRAMMING object-oriented programming, objects interact with each other by messages (specific codes). � The only thing that an object knows about another object is the object's interface. Each object's data and method is hidden from other objects. � In other words, the interface encapsulates the object's code and data.

DEFINE OOP 1 �A type of programming where the programmer can define data types and types of operation (function), which will be performed on the data structure. Data Matric No. Marks Data Type Integer Float Types of operation Sorting students Calculate marks

1 DEFINE OOP (CONT. ) � 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. � Object Oriented Programming is programming which is oriented around objects, thus taking advantage of Encapsulation, Polymorphism, and Inheritance to increase code reuse and decrease code maintenance.

DEFINE OOP (CONT. ) 1 �A language or technique is object-oriented if it directly supports: �Abstraction - providing some form of classes and objects. �Inheritance - providing the ability to build new abstractions out of existing ones. �Runtime polymorphism - providing some form of runtime binding.

2 HISTORY OF OOP � Early 1960 s Kristen Nygaard �SIMULA Ole-Johan Dahl was the first object language. �developed by Kristen Nygaard and Ole-Johan Dahl in Norway. �It was designed for the purpose of creating simulations (ships)

2 HISTORY OF OOP � 1970 s Alan Kay � Alan Kay – idea to integrated the SIMULA into personal computer � Joint venture with Xerox Parc – created the first personal computer called Dynabook � Smalltalk was the object-oriented language developed for programming the Dynabook � It was a simulation and graphics-oriented programming language.

2 HISTORY OF OOP � 1980 s Bjorn Stroustrup �Bjorn Stroustrup integrated object-oriented programming into the C language �The resulting language was called C++ and it became the first object-oriented language to be widely used commercially

2 HISTORY OF OOP � 1990 s James Gosling �a group at Sun led by James Gosling developed a simpler version of C++ called Java �Java programming meant to be a programming language for video-on-demand applications �No +ve response - re-oriented its focus and marketed Java as a language for programming Internet applications �The language has gained widespread popularity as the Internet has boomed

3 Ø Ø ADVANTAGES OF USING OOP Code extensibility q Ability to add codes, which are already existing and consistent with needs. Code reusability q Existing code can be tested first before it is inherited from previous module. q This will save cost and time needed to develop software. q With this method, it will help to increase programmer’s productivity. Represent real world q Using object-oriented concept, it will assist the programmer in creating a module because data used represents real situations. Data security q The use of encapsulation concept has made data to be protected from misuse by an unauthorized person.

4 BASIC TERMINOLOGIES OF OOP 1 Object 2 Class 3 Encapsulation 4 Data Abstraction 5 Inheritance 6 Polymorphism

4 BASIC TERMINOLOGIES OF OOP (CONT. ) 1 Object q Object is the term used to explain many things. §Example: student, chair and circle. q An Object consists of data and method. q 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. q Method is a set of function that manipulates data, such as method Determine. Status() can determine exam result for object student.

BASIC TERMINOLOGIES OF OOP (CONT. ) 4 2 Class q A set of objects that have similar attributes (data) and methods. q Attributes and methods of a class can be used by each object from that class Student { String name, address, status; int icno, sid; double marks; char Determine. Status() { if marks >= 40 status = “Pass”; else status = “Fail”; } } data method Class

4 BASIC TERMINOLOGIES OF OOP (CONT. ) 3 Encapsulation q 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. q It enables access to object just by using methods of that object. q It is one of the security features in OOP. q Attributes and methods of a class can be used by each object from that class. Class Student Name, Student ID, Address, IC No Calculate_result() Determine_grade() Print_result()

4 BASIC TERMINOLOGIES OF OOP (CONT. ) 4 Data Abstraction q Data abstraction is a process to delete all unnecessary attributes and remain the necessary attributes to describe an object q Attributes and methods of a class can be used by each object from that class. Class Box Characteristics Data abstraction length Object Box width Length, width, depth Behaviors depth Calculate_Volume() Calculate_Area() Figure 1. 2: Describe data abstraction concept in OOP for object Box.

4 BASIC TERMINOLOGIES OF OOP (CONT. ) 5 Inheritance q Create a new class from an existing class together with new attributes and behaviours. q The new class will have the same ability as the base class. q Use the concept of code reusability. Class C Class A Base class for B Class B Derived class from class A Base class for class C, D and E Class D Class E Derived class from class B

4 BASIC TERMINOLOGIES OF OOP (CONT. ) 6 Polymorphism q 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. q It is said to be “One interface, many methods”. Contoh: Method: Keluarkan wang anda dari bank: Objek: Pelajar 1 : Menggunakan mesin ATM yang disediakan oleh pihak bank di mana akaun dibuka Pelajar 2 : Menggunakan mesin ATM (MEPS) dari bank lain

6 STRUCTURED AND OOP APPROACH Pengaturcaraan Berstruktur 1 Berasaskan Fungsi Yang didefinisikan Pengaturcara OOP Teknik Pengaturcaraan Berasaskan Objek Memecahkan satu program yang besar Penggunaan konsep pengkapsulan pada beberapa fungsi. Setiap fungsi yang menggabungkan data dan fungsi akan melaksanakan tugas yang lebih dalam satu komponen (kelas) spesifik Contoh: class Individu{ void main( ){ ………. . // ………. . void Data. Peribadi( ) Peribadi (nama, umur); } main( ){ void Peribadi(char *a, int b) Individu a; data { //Definisi fungsi Data. Peribadi } /*Objek a capai data dan method dari kelas Individu*/ }

6 STRUCTURED AND OOP APPROACH (CONT. ) 2 Kod aturcara tidak boleh digunakan berulangkali 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 yang berulang 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

6 STRUCTURED AND OOP APPROACH (CONT. ) 3 Fungsi Memanipulasikan 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 mempakej data 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. 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.