• Object-oriented programming (OOP) is a style of programming that focuses on using objects to design and build applications. Contrary to procedure-oriented programming where programs are designed as blocks of statements to manipulate data, OOP organizes the program to combine data and functionality and wrap it inside something called an “Object”.

  • If you have never used an object-oriented programming language before, you will need to learn a few basic concepts before you can begin writing any code. This chapter will introduce some basic concepts of OOP:

  • Objects: Objects represent a real-world entity and the basic building block of OOP. For example, an Online Shopping System will have objects such as shopping cart, customer, product item, etc.

  • Class: Class is the prototype or blueprint of an object. It is a template definition of the attributes and methods of an object. For example, in the Online Shopping System, the Customer object will have attributes like shipping address, credit card, etc., and methods for placing an order, canceling an order, etc.

  • The four principles of object-oriented programming are: