Classes in OOP

In OOP, you derive objects from classes. In this section, we'll take a closer look at what a class actually is.

Classes are one of the most important concepts in OOP. You can say they are the building blocks of OOP. A class can be described as the blueprint of an object.

A class is like a template or blueprint that tells us what properties and behaviors an instance of this class will have. In most circumstances, a class itself can't actually do anything—it is just used to create objects. Let's look at an example to demonstrate what I am saying. Let's say we have a Human class. Here, when we say Human, we don't mean any particular person, but we are referring to a human being in general. A human that has two hands, two legs, and a mouth, and which can also walk, talk, eat, and think. These properties and their behaviors are applicable to most human beings. I know that this is not the case for disabled people, but for now, we will assume our generic human is able—bodied, keeping our example simple. So when we see the aforementioned properties and behaviors in an object, we can easily categorize that object as a human object or person. This classification is called a class in OOP.

Let's take a closer look at the properties and behaviors of a Human class. There are hundreds of properties that you can list for a human, but for the sake of simplicity, we can say that the following are the properties of a human being:

• Height
• Weight
• Age

We can do the same for behavioral properties. There are hundreds of particular behaviors that a person can perform, but here we will only consider the following:

• Walk
• Talk
• Eat