Description

GitHub Classroom

Lab 8 – OOP
A little story
In this lab we will code the story of the hare and the tortoise using OOP
Rules of the game
• The race:
• The distance is set in kilometers.
• Each day, the animals move a certain distance.
• The competitors:
• The hare: Fast (5 to 10 km/day), but might not move at all (50% chance).
• The tortoise: Slow (1 to 5 km/day), but always moves.
• Our goals:
• Create classes for the animals, allowing them to move and report their positions.
• Run the race, observing positions daily, until the finish line is reached.
• Apply and understand Python classes, objects, and inheritance.
Why no unit tests?
The participants

We will create these 3 classes with inheritance
Task 1: Create an Animal class
The Animal class is the parent class for our Hare and Tortoise classes. It provides the shared attributes and methods that all animals in this scenario have.
Attributes (TODO  __init__() )
• name: The name of the animal.
• position: The current position of the animal in the race. Initialized at 0.
• race_distance: The total distance of the race. This is used to determine when the race is finished.
Methods (TODO)
• move(): This method is to be implemented in each subclass to determine how the animal moves. In the Animal class, it’s left empty as a placeholder.
• report_position(): This method prints out the current position of the animal. You can print something like “The $name_of_object is at position $position_of_object”
• has_finished(): This method checks if the animal has reached or exceeded the race distance, and thus finished the race. Return a boolean
Task 2: The hare
This is a subclass of Animal. It inherits all the attributes and methods of Animal, but also has its own unique behavior.
Polymorphism (TODO)
Rewrite the move() method to follow these behaviors:
• The hare moves faster (between 5 and 10 kilometers per day) but there’s a 50% chance it doesn’t move at all, simulating the hare’s tendency to rest.
• Each day (each turn in our program), the hare will move a certain distance or rest, and its position will be updated accordingly.
Hints: for the resting time probability you can use random() and for the position increment you can get a random distance between 5 to 10 using randint()
Task 2: The hare
Note: to inherit all the attributes from a superclass you can simply write
class Hare(Animal):
def __init__(self, race_distance): super().__init__(“Hare”, race_distance)
Super() simply refers to the superclass (in this case the class animal) such that we can reuse its __init__ method If you do not want to use super():
class Hare(Animal): def __init__(self, race_distance):
self.name = “Hare” self.position = 0
self.race_distance = race_distance
Task 3: The tortoise
This is a subclass of Animal. It inherits all the attributes and methods of Animal, but also has its own unique behavior.
Polymorphism (TODO)
Rewrite the move() method to follow these behaviors:
• The tortoise moves slower (between 1 and 5 kilometers per day), but it moves every day, simulating the tortoise’s steady pace.
• Each day (each turn in our program), the tortoise will move a certain distance, and its position will be updated accordingly.

Task 4: Start the race
Now that everybody is ready, we can start the race
# Running the race race_distance = 50 hare = Hare(race_distance) tortoise = Tortoise(race_distance)
while not hare.has_finished() and not tortoise.has_finished(): hare.move() tortoise.move() hare.report_position() tortoise.report_position()
if hare.has_finished() and tortoise.has_finished(): print(“It’s a tie!”)
elif hare.has_finished():
print(“The hare wins!”)
else: print(“The tortoise wins!”)