Computer Science Programming Basics in Ruby

10.5 Applications

Inheritance is a way to form new classes that borrow attributes and behaviors of previously defined classes. After learning about inheritance and method overriding, you are probably wondering when you will ever need to use them. What is the big deal about inheritance? Why can’t we just make a bunch of different classes? To put it simply, it saves significant unnecessary coding by eliminating code duplication, and it simplifies software testing and maintenance since functionality and local data are isolated. Here are several other examples for which you can use inheritance.

10.5.1 Person Database

A contractor is looking for a way to keep track of all the people in his organization. He has full-time and part-time employees, student interns, and volunteers. In this example, you can make a class called Person. This class can have the individual’s name, address, phone number, email address, and weekly hours worked. You can have a method called email that emails all the employees to remind them to turn in their time sheets. Then you can have subclasses called Full, Part, Intern, and Volunteer. For the Full subclass, you can include variables like hourly wage and overtime pay. For a behavior you can have a process_payment method to deposit money into the employee’s bank account. A student Intern would have different variables. Maybe you want to keep track of who has the highest grade-point average or test scores to see which one is the top intern. Thus, you would ...