This document provides an overview of object-oriented programming concepts in Ruby, including classes, objects, inheritance, and the constructor. It discusses how Ruby uses classes and objects to design applications. Key concepts covered are abstraction, encapsulation, polymorphism, and inheritance. Classes specify the form of an object and combine data representation and manipulation methods. Objects are instances of classes that can communicate by sending and receiving messages. The constructor initializes an object's state when created. Inheritance allows new classes to extend existing classes.

1. Object-oriented
programing in Ruby
Ngoc Nguyen

2. Overview
❖ Introduction
❖ Class
❖ Object
❖ Inheritance
❖ Super method

3. OOP in Ruby
❖ Uses Object and their interactions to design application
and computer programs
❖ Basic Concepts
➢ Abstraction
➢ Polymorphism
➢ Encapsulation
➢ Inheritance

4. Basic Concepts
❖ Abstraction
➢ simplifying complex reality by modeling class appropriate to the
problem.
❖ Polymorphism
➢ process of using a operator or function in different ways for different
data input.

5. Basic Concepts
● Encapsulation
o hides the implementation of a class from other object
● Inheritance
o a way to form new classes using classes that have already been
define

6. Class
❖ is used to specify the form of an object
❖ combines data representation and methods for
manipulating that data into one packet
❖ data and methods in class are members of class

7. Object
❖ are basic building blocks of OOP program
❖ combination of data and methods
❖ communicate together throught methods
❖ can receive, send message, process data

8. Object
❖ Two steps in creating object
➢ define a class
➢ run a instance of that particular class

9. The constructor
❖ special kind of method
❖ automatically called when object is created
❖ initiate the state of an object
❖ called is `initialize`

10. The Constructor
❖ object’s attributes - instance variables or member fields
➢ data items into that object
❖ `allocate` method
➢ create object without constructor

11. Constructor Overloading
❖ has no constructor overloading
➢ object is created with default parameter values

12. Methods
❖ are functions defined inside the body of class
❖ used to perform operations with object’s attributes

13. Methods
❖ instance methods
➢ the method that the object contains
❖ class methods
➢ the method that created by self class
➢ define: “self.method_name”

14. Accessor & Setter methods
❖ to make variables available from outsite class
❖ define variables (set values)

15. Inheritance
❖ newly formed classed are called derived classes
❖ the classes that we derive from are called base classes
❖ the devired classes override or extend the functionality
of base classes

16. Inheritance
❖ use `<` operator to create inheritance relations
❖ `super` method to call parent function
❖ `ancestors` method to show lists of ancestors

17. The super method
❖ call a method of the same name in the parent’s class
❖ super
➢ passed all arguments to parent’s classes
❖ super()
➢ no arguments passed to perent’s classes

18. References
❖ Object oriented Ruby
➢ http://www.tutorialspoint.com/ruby/ruby_object_oriented.htm
❖ Object-oriented programming in Ruby
➢ http://zetcode.com/lang/rubytutorial/oop/