Cookie Jar

Source: Sesame Street

Suppose that you’d like to implement a cookie jar in which to store cookies. In a file called jar.py, implement a class called Jar with these methods:

• __init__ should initialize a cookie jar with the given capacity, which represents the maximum number of cookies that can fit in the cookie jar. If capacity is not a non-negative int, though, __init__ should instead raise a ValueError (via raise ValueError).
• __str__ should return a str with \(n\) 🍪, where \(n\) is the number of cookies in the cookie jar. For instance, if there are 3 cookies in the cookie jar, then str should return "🍪🍪🍪"
• deposit should add n cookies to the cookie jar. If adding that many would exceed the cookie jar’s capacity, though, deposit should instead raise a ValueError.
• withdraw should remove n cookies from the cookie jar. Nom nom nom. If there aren’t that many cookies in the cookie jar, though, withdraw should instead raise a ValueError.
• capacity should return the cookie jar’s capacity.
• size should return the number of cookies actually in the cookie jar.

Structure your class per the below. You may not alter these methods’ parameters, but you may add your own methods.

class Jar:
    def __init__(self, capacity=12):
        ...

    def __str__(self):
        ...

    def deposit(self, n):
        ...

    def withdraw(self, n):
        ...

    @property
    def capacity(self):
        ...

    @property
    def size(self):
        ...

Demo

You’re welcome, but not required, to implement a main function in which to test your class, so this is all we can demo!

Source: Sesame Street

Before You Begin

1. Log into code.cs50.io using your GitHub account.
2. Click inside the terminal window and execute cd.
3. Execute wget https://cdn.cs50.net/2022/fall/labs/6/jar.zip followed by Enter in order to download a zip called jar.zip in your codespace. Take care not to overlook the space between wget and the following URL, or any other character for that matter!
4. Now execute unzip jar.zip to create a folder called jar.
5. You no longer need the ZIP file, so you can execute rm jar.zip and respond with “y” followed by Enter at the prompt.

How to Test

Here’s how to test your code manually:

• Define a main function in your jar.py file, wherein you create a new instance of Jar with jar = Jar(). Test this jar has the capacity it should by calling print(str(jar.capacity)). Be sure your program calls main at the bottom of the file, as via main().
• Test that your __str__ function works as intended by calling print(str(jar)).
• Try calling jar.deposit(2) to deposit two cookies. Calling print(str(jar)) should now show you the same number of cookies you’ve deposited.
• Try calling jar.withdraw(1) to withdraw one cookie. Calling print(str(jar)) should now show you one fewer cookie than you had before.
• Try experimenting with depositing and withdrawing various amounts of cookies. Are you unable to withdraw past the jar’s size? Are you unable to deposit past the jar’s capacity?

No check50 for this one!

How to Submit

No need to submit! This is a practice problem.