Generating classes to create objects

Imagine that we have to draw and calculate the perimeters and areas of three different rectangles. You will end up with three rectangles drawn with their widths and height values and their calculated perimeters and areas. It would be great to have a blueprint to simplify the process of drawing each rectangle with their different width and height values.

In object-oriented programming, a class is a template definition or blueprint from which objects are created. Classes are models that define the state and behavior of an object. After declaring a class that defines the state and behavior of a rectangle, we can use it to generate objects that represent the state and behavior of each real-world rectangle.

Note

Objects are also known as instances. For example, we can say each rectangle object is an instance of the Rectangle class.

The following picture shows two rectangle instances named rectangle1 and rectangle2. These instances are drawn with their width and...