Object Oriented Programming_Lecture 2

Object Oriented Programming_Lecture 2

• 1.
  Object Oriented Programming Chapter1: Introduction to OOP Prepared by: Mahmoud Rafeek Alfarra 2016
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  Outlines ◉ What isObject-Oriented Programming ? ◉ Procedural vs. Object-Oriented Programming ◉ OO Programming Concepts ◉ Concept of Objects and classes ◉ UML Class Diagram ◉ Visibility Modifiers and Accessor Methods ◉ Full Example
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  Lecture Let’s think onconcept of Class and Object 2
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  (‫ى‬َ‫م‬ْ‫ع‬َ‫أ‬ ِ‫ة‬َ‫م‬‫ا‬َ‫ي‬ِ‫ق‬ْ‫ل‬‫ا‬ َ‫م‬ْ‫و‬َ‫ي‬ُ‫ه‬ُ‫ر‬ُ‫ش‬ْ‫ح‬َ‫ن‬َ‫و‬ ‫ًا‬‫ك‬‫ن‬َ‫ض‬ ً‫ة‬َ‫ش‬‫ي‬ِ‫ع‬َ‫م‬ ُ‫ه‬َ‫ل‬ ََّ‫ن‬ِ‫إ‬َ‫ف‬ ‫ي‬ِ‫ر‬ْ‫ك‬ِ‫ذ‬ ْ‫ن‬َ‫ع‬ َ‫ض‬َ‫ر‬ْ‫ع‬َ‫أ‬ ْ‫ن‬َ‫م‬َ‫و‬) ‫ه‬‫ط‬ ‫ة‬‫ر‬‫و‬‫س‬
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  Classes & Objects!
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  o Classes areconstructs that define objects of the same type. o “Class” refers to a blueprint. It defines the variables and methods the objects support. What is Class ? Class Name: Circle Data Fields: radius is _______ Methods: getArea A class template
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  o “Object” isan instance of a class. o Each object has a class which defines its data and behavior. o An object has both a state and behavior. o The state defines the object, and the behavior defines what the object does. What is Object? Class Name: Circle Data Fields: radius is _______ Methods: getArea Circle Object 1 Data Fields: radius is 10 Circle Object 2 Data Fields: radius is 25 Circle Object 3 Data Fields: radius is 125 A class template Three objects of the Circle class
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  Class & Object
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  Class & Object
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  Class & Object
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  Class & Object
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  Thinking to buildclass … Any Thing Attributes Behavior Each one is presented as a variable in the Class Each one is presented as a method in the Class A new class will be considered as a new data type, so you can declare a variables (Objects) of them and then you can set and get data to its properties.
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  o A Javaclass uses variables to define data fields and methods to define behaviors. o Additionally, a class provides a special type of methods, known as constructors, which are invoked to construct objects from the class. Thinking to build class …
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  Thinking to buildclass … class Circle { /** The radius of this circle */ double radius = 1.0; /** Construct a circle object */ Circle() { } /** Construct a circle object */ Circle(double newRadius) { radius = newRadius; } /** Return the area of this circle */ double getArea() { return radius * radius * 3.14159; } } Data field Method Constructors
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  How to buildmy class? Access_modifiers class class_name { // variables = attributes Access_modifiers class_name(par1, par2, …) { } // behavior = methods } Always, the class has a method called constructor which gives initial values to the attributes of class Is a reserved word The identifier of class Must be as any variable
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  o A classcan have three kinds of members:  fields: data variables which determine the status of the class or an object  methods: executable code of the class built from statements. It allows us to manipulate/change the status of an object or access the value of the data member  nested classes and nested interfaces Class Members
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  How to insatiateobject? class_name object_name = new class_name (arg1, arg2, …); The name of class, which you want to insatiate an object of it. Reserved word Values based on the parameters of constructor The name of object
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  UML Class Diagram Circle radius:double Circle() Circle(newRadius: double) getArea(): double circle1: Circle radius = 1.0 Class name Data fields Constructors and methods circle2: Circle radius = 25 circle3: Circle radius = 125 UML Class Diagram UML notation for objects
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  Practices Group 1 Compare between constructorand methods in class. Group 2 Detect 3 classes from your bedroom and 2 objects. Group 3 Diffrenciate between Class & Object Group 4 Draw the UML Class Diagram of Course class. Group 5 Draw the UML Class Diagram of Student class. Group 6 Thinking to build Circle class.
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  THANKS! Any questions? You canfind me at: Fb/mahmoudRAlfarra Staff.cst.ps/mfarra Youtube.com/mralfarra1 @mralfarra