Explore OOP in C++ to write cleaner, modular, and scalable code. Learn classes in C++, data hiding, encapsulation, abstraction, inheritance, and polymorphism in C++.

Become  a C++ Programmer

This module aims to teach us how to write cleaner, more modular, and scalable code in C++ by providing an understanding of OOP in C++. We'll start with the basics of object-oriented programming and build up to advanced concepts such as inheritance, data hiding, and polymorphism. Along the way, we'll explore how each concept applies to C++ and how various C++ features facilitate OOP.

Object-Oriented Programming in C++

The private data members of a class are only accessible through the functions present in that class. Nothing from outside can manipulate the class object without using its functions. 

What if we need to access class variables in a function which is not a part of the class? That function would have to become a **friend** of the class.

> A friend function is an independent function which has access to the variables and methods of its befriended class.

To create a friend function for a class, it must be declared in the class along with the `friend` keyword.  

Let's create a `Ball` class to explain this better:

We'll take a look at a special category of functions called friends.

Friend Functions