Cash

Problem to Solve

In a file called cash.py in a folder called sentimental-cash, write a program that asks the user how much change is owed and then spits out the minimum number of coins with which said change can be made. You can do this exactly as you did in Problem Set 1, except that your program this time should be written in Python, and you should assume that the user will input their change in dollars (e.g., 0.50 dollars instead of 50 cents).

Demo

Specification

Use get_float from the CS50 Library to get the user’s input and print to output your answer. Assume that the only coins available are quarters (25¢), dimes (10¢), nickels (5¢), and pennies (1¢).
- We ask that you use get_float so that you can handle dollars and cents, albeit sans dollar sign. In other words, if some customer is owed $9.75 (as in the case where a newspaper costs 25¢ but the customer pays with a $10 bill), assume that your program’s input will be 9.75 and not $9.75 or 975. However, if some customer is owed $9 exactly, assume that your program’s input will be 9.00 or just 9 but, again, not $9 or 900. Of course, by nature of floating-point values, your program will likely work with inputs like 9.0 and 9.000 as well; you need not worry about checking whether the user’s input is “formatted” like money should be.
If the user fails to provide a non-negative value, your program should re-prompt the user for a valid amount again and again until the user complies.
Incidentally, so that we can automate some tests of your code, we ask that your program’s last line of output be only the minimum number of coins possible: an integer followed by a newline.

How to Test

While check50 is available for this problem, you’re encouraged to first test your code on your own for each of the following.

Run your program as python cash.py, and wait for a prompt for input. Type in 0.41 and press enter. Your program should output 4.
Run your program as python cash.py, and wait for a prompt for input. Type in 0.01 and press enter. Your program should output 1.
Run your program as python cash.py, and wait for a prompt for input. Type in 0.15 and press enter. Your program should output 2.
Run your program as python cash.py, and wait for a prompt for input. Type in 1.60 and press enter. Your program should output 7.
Run your program as python cash.py, and wait for a prompt for input. Type in 23 and press enter. Your program should output 92.
Run your program as python cash.py, and wait for a prompt for input. Type in 4.2 and press enter. Your program should output 18.
Run your program as python cash.py, and wait for a prompt for input. Type in -1 and press enter. Your program should reject this input as invalid, as by re-prompting the user to type in another number.
Run your program as python cash.py, and wait for a prompt for input. Type in foo and press enter. Your program should reject this input as invalid, as by re-prompting the user to type in another number.
Run your program as python cash.py, and wait for a prompt for input. Do not type anything, and press enter. Your program should reject this input as invalid, as by re-prompting the user to type in another number.

Correctness

check50 cs50/problems/2024/x/sentimental/cash

Style

style50 cash.py

How to Submit

submit50 cs50/problems/2024/x/sentimental/cash

Why does my submission pass check50, but shows “No results” in my Gradebook after running submit50?

In some cases, submit50 may not grade the assignment due to inconsistent formatting in your cash.py file. To fix this issue, run black cash.py in the sentimental-cash folder. Address any issues that are revealed. Run check50 again to ensure your submission still functions. Finally, run the submit50 command above again. Your result will appear in your Gradebook within a few minutes.

Please note that if there is a numerical score next to your cash submission in the submissions area of your Gradebook, the procedure discussed above does not apply to you. Likely, you have not fully addressed the requirements of the problem set and should rely upon check50 for clues as to what work remains.