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8. 8 Concept of Encapsulation What is encapsulation? - data and functions/methods are packaged together in the class normally with the same scope of the accessibility in the memory Why encapsulation - Objects no longer need to be dependent upon any “outside” functions and data after the creation - Provide ADT (Abstract Data Types) - Easier in coding - Promote standards in OOP

9. YG - CS1709

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13. YG - CS17013 Classes vs. Objects Class is a data structure that encapsulates data and functions. Data in a class are called member data, class variables, instance variables, or fields. Functions in a class are called member functions or methods. Constructors are special methods. Objects are the instance of a class. Creation of the objects and instantiation of the objects are all referring to memory allocation to hold the data and methods of the objects. In Java, all objects are created dynamically using new operator. For example: ClassName ObjName = new ClassName();

14. YG - CS17014

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23. YG - CS17023 Characteristics of Constructors A special method that has the same name of the class without return type, not even void. Constructor will be automatically called whenever an object is created. Like a method, constructor can be overloaded for the flexibility of the object creation. A super class constructor can be called by a sub class object as: super();

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26. YG - CS17026 In OOP, particularly in Java, get() means to return one of object’s member data get() usually has a return type and takes no argument Use meaningful name for a get() method get methods

27. YG - CS17027 In OOP, particularly in Java, set() means to set object’s member data set() usually has void return and takes argument(s) to set the member data set() also checks the validity of the data before it sets Use meaningful name for a set() method set methods

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51. YG - CS17051 Static Fields What is a static field?  a variable that is not associated with any instance of the class, therefore it’s a class-wide field/variable/data  a variable that can be used without creation of the object  a private static field can be only use within the current class  can be constant (final), so it’s value cannot be modified; must be initialized when declaring Why static fields?  keep tracking class-wide information  Convenient to use and save memory  Be careful data encapsulation in using static fields

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76. YG - CS17076