Ex. 1 Design and implement a project containing at least three classes, the first being a general category, the second one derived from it, and the third one derived from the second, after the model of the Socrates program discussed in class.

General requirements:

• Each class should declare at least 2 data members as protected. There should be at least an accessor function for each of them (as the function Is_alive is for the data member life_flag in the class Lifeform) and mutator functions when appropriate (like the function Die for the same life_flag).
• Each class should implement at least one constructor. The constructor(s) of the derived class should invoke a constructor of the base class.
• Each class should implement at least two other class methods declared as public. One of these class methods should be implemented with the same name in at least one base class and one derived class, as an example of redefining/overloading a class method, as it is the case for the function Walk in the Socrates example.
• The main should contain some examples of declaring objects from each of your classes and of calling the available methods for each of them.

Ideas:

• Any three categories in the natural systems other than lifeform, animal and human - plants, specific types of animals, reptiles, mammals, birds, etc.
• Utility objects: vehicles of different categories, inanimate objects followed by human made machines and robots, and so on.
• Different types of products to be sold in a shop, provided that you don't reuse the class Product defined before.
• A general file category, followed by a viewable file and then image file or text file.
• Different categories for professions, anything other than student and teacher.

Note. Do not implement the same classes as someone else. You can have at most one class name in common with someone else, but the content of the class should be different.

Example The following files constitute the program implementing the Socrates example, along with a Makefile for compilation on Linux:
animal.cpp
animal.h
human.cpp
human.h
lifeform.cpp
lifeform.h
main.cpp
Makefile

Turn in: all the files in your project (.cpp and .h). If you create a Makefile, send it in too.