Introduction to Object Orientation

Dr. Ahmed Youssef

Object-Orientation It is a kind of thinking methodologyEverything in the world is an object;

Any system is composed of objects;

The evolution and development of a system is caused by the interactions among the objects inside or outside the system

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Decomposition of the large problem into small parts that can be solved separately.

Why Object Oriented?

Large Application

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Object-Oriented Concept

Object & Class InheritancePolymorphismEncapsulation

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Everything in the world is an object

A flower, a tree, an animal A student, a professor A desk, a chair, a classroom,

a building A university, a city, a country The world, the universe A subject such as CS, SWE,

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Object

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Any system is composed of objectsA cultural systemAn educational systemAn economic systemAn Information systemA computer system

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Procedure Program view

Main Program

Data

Procedure1

Procedure2

Procedure3

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Main Program(Also a module)

Data

Data Data1

Module2

+

Data Data2

Module1

+

Data Data1

Procedure1Procedure2

The main program coordinates calls to procedures in separate modules and hands over appropriate data as parameters.

Procedure3

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Object1

Data1+Procedures1

Data Data1Object3

Data3 + Procedures3

Object2

Data2 + Procedures2

Object4

Data4 + Procedures4

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Classesobjects sharing common characteristics

containstate: attributes, fields, variables, data member

behavior: functions, methods

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Class

Person

Ahmed

Majed

Salem

Saad

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Class

Student

Ahmed

Majed

Salem

Saad

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Class

Tennis Player

Bandar

Mosaed

Nayef

Khaled

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Class

Institute

Social Technology

Engineering

Science

Agricultural Technology

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Class

NameAttributesOperations

…

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ClassStudent

StudentIDFirstNameLastNameAddressetc…

RegisterForCourseDropCourseetc...

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ClassTennis Player

FirstNameLastNameNationalityRankingetc…RegisterForTournamentetc...

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Class Car

Car Reg. NumberMakerModelColoretc…AccelerateStopetc...

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ClassAirplane

Plane NumberManufacturerModeletc…TakeOffLandingetc...

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Object & Class

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Object & ClassStudent

StudentIDFirstNameLastNameAddressetc…

RegisterForCourseDropCourseetc...

Student

Ahmed

Majed

Salem

Saad

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Object & ClassStudent1

B4555555AhmedAlfgdfg7146 sdasds7etc…

RegisterForCourseDropCourseetc...

Student

Ahmed

Majed

Salem

Saad

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Student1

B4555555AhmedAlfgdfg7146 sdasds7etc…

RegisterForCourseDropCourseetc...

Student

StudentIDFirstNameLastNameAddressetc…

RegisterForCourseDropCourseetc...

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Building Class

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Any Thing

Attributes

Behavior

Student- Class

Lname string Student_ID

string

Levelint

Telstring

Gender string

Programstring

Print_infoInput: -return: voidUpdate_i

nfoInput: name or IDReturn : void

Fname string

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MainClass

StudentClass

3.

Man

age

obje

ct

1. Create objects from

class

Obj1

Obj2

Obj3

Obj4

2. objects

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Student Class

Instance variable

Constructor

Constructor

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Method

OverloadedMethod

Student Class

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