Problem Set 2

Collaboration on problem sets is not permitted except to the extent that you may ask classmates and others for help so long as that help does not reduce to another doing your work for you, per the course’s policy on academic honesty.

What to Do

Log into cs50.dev using your GitHub account using Chrome, Edge, or Safari, not Firefox
Run update50 in your codespace’s terminal window to ensure your codespace is up-to-date and, when prompted, click Rebuild now
Submit Scrabble
Submit Readability
Submit one of:
- Caesar, if feeling less comfortable
- Substitution, if feeling more comfortable

If you submit both Caesar and Substitution, we’ll record the higher of your two scores.

When to Do It

By 2026-09-20T23:59:00-04:00.

How to Get Help

Browse or search for answers on Ed!
Verbalize your logic to a rubber duck (whether actual or virtual!) and see if you hear any illogic in your own words!
Attend office hours!
Email heads@cs50.harvard.edu!

Advice

To see the manual pages for C functions, visit manual.cs50.io.
If you see any errors when compiling your code with make, focus first on fixing the very first error you see, scrolling up as needed. If unsure what it means, look just below it: help50 will offer a hint in yellow if it recognizes the error, or a help50 button atop your terminal window that you can click to ask the duck about it.