Coke Machine

CS50 Coke Bottle

Suppose that a machine sells bottles of Coca-Cola (Coke) for 50 cents and only accepts coins in these denominations: 25 cents, 10 cents, and 5 cents.

In a file called coke.py, implement a program that prompts the user to insert a coin, one at a time, each time informing the user of the amount due. Once the user has inputted at least 50 cents, output how many cents in change the user is owed. Assume that the user will only input integers, and ignore any integer that isn’t an accepted denomination.

Demo

Before You Begin

Log into code.cs50.io, click on your terminal window, and execute cd by itself. You should find that your terminal window’s prompt resembles the below:

$

Next execute

mkdir coke

to make a folder called coke in your codespace.

Then execute

cd coke

to change directories into that folder. You should now see your terminal prompt as coke/ $. You can now execute

code coke.py

to make a file called coke.py where you’ll write your program.

How to Test

Here’s how to test your code manually:

  • Run your program with python coke.py. Type 25 and press Enter. Your program should output:
    Amount due: 25   
    

    and continue prompting the user for coins.

  • Run your program with python coke.py. Type 10 and press Enter. Your program should output:
    Amount due: 40
    

    and continue prompting the user for coins.

  • Run your program with python coke.py. Type 5 and press Enter. Your program should output:
    Amount due: 45
    

    and continue prompting the user for coins.

  • Run your program with python coke.py. Type 30 and press Enter. Your program should output:
    Amount due: 50
    

    and continue prompting the user for coins.

  • Run your program with python coke.py. Type 25 and press Enter, then type 25 again and press Enter. Your program should halt and display:
    Change owed: 0
    
  • Run your program with python coke.py. Type 25 and press Enter, then type 10 and press Enter. Type 25 again and press Enter, after which your program should halt and display:
    Change owed: 10
    

You can execute the below to check your code using check50, a program that CS50 will use to test your code when you submit. But be sure to test it yourself as well!

check50 cs50/problems/2022/python/coke

Green smilies mean your program has passed a test! Red frownies will indicate your program output something unexpected. Visit the URL that check50 outputs to see the input check50 handed to your program, what output it expected, and what output your program actually gave.

How to Submit

In your terminal, execute the below to submit your work.

submit50 cs50/problems/2022/python/coke