Introduction

In order to understand the Object-Oriented Programming (OOP) approach, we should start by discussing the procedural-oriented programming approach first. The procedural approach is the conventional way of writing code in high-level languages where a problem is considered a sequence of things to be performed, such as walking, eating, reading, and so on. A number of functions can be written to accomplish such tasks. The procedural approach organizes a set of computer instructions into groups called procedures – also known as functions. Therefore, functions are first-class citizens in your code. When we focus that much on functions, consequently, the data gets less attention.

In a multi-function program, despite the fact that functions can house local data, a lot of important data is defined as global data. Several functions might operate on such global data and, therefore, the data might become vulnerable. Also, such an approach might not establish a secure way...