OOP

Each object has a unique identity.
Each object can contain several other objects.
Each object can have a series of attributes.
Every object has a set of behaviors.
An object is an instance created from a class. The process of making this sample is called instantiation.

4 fundamental concepts of object oriented programming

Abstraction
- When we talk about "animal", we are not referring to a specific animal. This is an abstract concept.
- Abstraction occurs when a programmer hides irrelevant data about an object or class to reduce complexity.
Polymorphism
- Ability to take different forms.
  - With inheritance and class method
  - With function
Inheritance
- Is a mechanism that allows one class to inherit the properties of another class, in the same way that a child inherits certain properties from each of its parents.
Encapsulation
- Means "putting one or more items in a physical or logical package." Encapsulation in object-oriented programming limits access to implementation details.
- Is implemented by access specifiers. Access level attributes define the scope of class members.
  - Access Modifiers
    - public
    - protected
    - private