Exercise Notes

Zooville Saga

Getting started

This exercise is to give you some practice working with classes, objects, and inheritance, where the child objects can have specific methods which call more general methods of the parent object(s).

You have been assigned to a team that’s creating the next big thing: Zooville Saga! Your job is to create the basic data structure for the animals. They each have a hunger meter (out of 100), a name, and a species. They will also each need a method that’s called whenever the player feeds them that feeds it and lets the player know which animal was fed and how full it is (just on the console will do).

Once you’ve gotten the basics ready, make some animals! How about a zebra and a lion?

Here’s a starting point:

class Animal:
    def __init__(self, name, species):
        # ...
    
    def feed(self):
        # ...

Carnivores and herbivores

The team member working on the UI has hooked up your code to their UI and the players are delighted! But a game designer has told you that they need something else to make it an actual game (who’d have thought?).

The zoo starts with £4000, and animal feed costs different amounts depending on what type of food the animal eats! Herbivore feed costs £200 and carnivore feed costs £500.

Create herbivore and carnivore classes and link them to your animal class, then add their own feed_herbivore_food and feed_carnivore_food methods. Then, make some more animals in addition to your zebra and lion… how about a chinchilla and a ferret?

Your zoo finances are tracked here:

class Zoo:
    cash = 4000
    def spend(self, amount):
        if (self.cash < amount):
            raise Exception("Not enough money!")
        self.cash -= amount
        print(f'Remaining funds: {self.cash}') 

my_zoo = Zoo()

Food types

The game producer is here and has asked another thing of you. In order to make the animal animations more appropriate, they need to eat different things depending on the animal, and then the message the player receives should be appropriate to the food too!

Oh dear… that means that the zebra is a herbivore that eats grass, the chinchilla a herbivore that eats fruits and seeds, the lion a carnivore that eats large prey, and the ferret a carnivore that eats small prey.

For some reason, you’ve been told the only difference is the graphic – i.e. the food_type class variable that you’ll need to add – even though in reality lion food would probably cost more than ferret food…

You should have everything you need to implement this step of the exercise.

Animal creation

Oh no! A freak thunderstorm blew up exactly the part of the code that wired up animal creation! And the person who originally wrote the code is on holiday! What a disaster. It’s up to you to write it again.

You have a class that creates animals, but not of any particular species:

class AnimalCreator:
    def create_animal(self, animal_type, name):
        animal = animal_type(name)
        return animal
    
    def create_lion(self, name):
        # Implement me

    ...

Add methods onto AnimalCreator for each of Zebra, Lion, Chinchilla, and Ferret.