Objected Oriented Programming(OOP)

Classes represent concepts. Objects are instances of classes.

a new class will have:

• Properties or states (characteristics): that describe an object
• behavior (what can it do or what can it be done to it)

both are modified through:

• attributes: parameters that define the state of the object
• methods: functions that define the behavior of the object

Concepts in OOP:

• SOLID Principles
• Encapsulation: states and behaviors are closed in one single unit.
• Abstraction: abstraction hides the internal implementation of attributes and methods, giving external agents only what they need.
• Inheritance: Deriving a class from another class.
• Polymorphism: The ability to substitute classes with similar functionality.
  • Method Overriding(Dynamic Polymorphism): when subclass changes (overrides) the method (function) of the superclass.
  • Method Overloading(Static Polymorphism): When method binding(linking a method to the call) happens at compile time and it depends on the reference of the class.
  • Duck Typing: an object is of a given type if it has all methods and properties required by that type. I.e. methods and properties identify object’s type, not it’s inheritance.
• Inheritance Relationships: Inheritance Relationships can be either “Is-A”, or “Has-A”.