Indoor Voice


Best to use your “indoor voice” sometimes, writing entirely in lowercase.

In a file called, implement a program in Python that prompts the user for input and then outputs that same input in lowercase. Punctuation and whitespace should be outputted unchanged. You’re welcome, but not required, to prompt the user explicitly, as by passing a str of your own as an argument to input.


Before You Begin

Execute cd by itself in your terminal window. You should find that your terminal window’s prompt resembles the below:


Next execute

mkdir indoor

to make a folder called indoor in your codespace.

Then execute

cd indoor

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


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


How to Test

Here’s how to test your code manually. At the indoor/ $ prompt in your terminal: :

  • Run your program with python Type HELLO and press Enter. Your program should output hello.
  • Run your program with python Type THIS IS CS50 and press Enter. Your program should output this is cs50.
  • Run your program with python Type 50 and press Enter. Your program should output 50.

If you run into an error saying your file cannot be opened, retrace your steps to be sure that you are inside your indoor folder and have saved your file there. Remember how?

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/indoor

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/indoor