4 Characteristics of OOP

• Encapsulation
  • A method of making the form of data and code unknown to the outside, and structuring the data's structure, role, and function into a single capsule.
• Abstraction
  • Expressing common characteristics (variables, methods) of classes by grouping them together.
• Inheritance
  • Using variables and methods defined in a parent class by inheriting them in a child class.
• Polymorphism
  • Refers to a structure that can be expressed in various forms.

Encapsulation #

A method of making the form of data and code unknown to the outside, and structuring the data's structure, role, and function into a single capsule (information hiding).

• Encapsulation Methods
  1. Attach the access modifier private before member variables. (private: accessible only within its own class)
  2. Create methods to set and retrieve values for member variables (getter, setter).

Abstraction #

Expressing common characteristics (variables, methods) of classes by grouping them together.

Inheritance #

Using variables and methods defined in a parent class by inheriting them in a child class.

e.g.) Using the extends keyword

Polymorphism #

The ability for an object to respond in its own unique way to a single message when performing an operation based on that message.

• Methods Supporting Polymorphism
  • Overloading
  • Overriding

Overloading #

Defining multiple methods with the same name within a single class.

Overriding #

Changing and using the content of a method inherited from a parent class. Parameters and return type must be the same.