Object Oriented Programming Concepts Explained

The page defines object oriented programming as the use of objects that contain both data and methods that interact with each other. It says a language needs objects, classes, encapsulation, inheritance, abstraction, and polymorphism to count as object oriented.

Reading notes

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• Encapsulation keeps an object’s state private and lets other objects change it only through public methods.
• The cat example shows private fields and a private meow() method, with public methods like Sleep, Play, and Feed changing the state.
• Inheritance creates a hierarchy where child classes reuse fields and methods from a parent class and add their own unique methods.
• The teacher and student example shows both as Person classes, with subject for Teacher and school for Student.
• Abstraction shows only a high-level interface and hides internal implementation details from other objects.
• The cell phone example says users know what the buttons do without knowing how they work behind the scenes.
• Polymorphism means one interface can be used by different object types, each with its own version of that interface.
• The figure example says star, circle, and rectangle share methods like calculateSurface() and calculatePerimeter(), but each computes them differently.