Student Guide

CS30 is the coding-lab tool your course uses for labs and exams. This page covers everything you need to use it: signing in, finding your lab, writing and running code, and what to expect during a proctored (locked-down) exam.

Signing in

Sign in with your school Google account. You can only be signed in from one place at a time — if you log in somewhere else, your other session ends.

  • On the web, you’re taken straight to Google’s sign-in page and back.
  • In the desktop app, signing in opens your system’s default browser to complete the same Google sign-in, then returns you to the app.

Finding your lab

Labs are only open during their scheduled window. If you try to open a lab before it starts or after it ends, you won’t be able to get into it — check with your TA if you think a lab should be open and isn’t.

Once a lab is open, you’ll see the list of problems in it. Pick one to open the editor.

Using the editor

Write your code in the editor panel. You don’t need to save manually — your work autosaves automatically roughly every 60 seconds, and again when you leave the lab, so you shouldn’t lose progress if your browser or the app closes unexpectedly.

Run vs. Submit

  • Run checks your code against the sample test cases shown on the problem. Use this as much as you want while you’re working — it doesn’t affect your grade.
  • Submit is what actually gets graded. It runs your code against the full set of grading tests and records the result.

You can submit more than once; check with your TA or course policy for how multiple submissions are handled.

During a proctored (lockdown) lab

Some labs — usually exams — run in a locked-down, fullscreen mode that keeps track of what happens in the window while it’s open. This isn’t meant to be a surprise, so here’s exactly what it watches for:

  • Leaving fullscreen, or switching away to another window or tab
  • Pasting content that came from outside the app
  • Opening the browser/app’s developer tools
  • Right-clicking (the context menu)
  • Copying something out through the clipboard in a way the app can’t see
  • The window being minimized and restored

Avoid all of the above during a locked-down lab — each one is logged, and your TA can see it. If something happens that you can’t avoid (your computer needs a restart, a real emergency, an app crash), don’t panic — just contact your TA afterward and explain what happened.

If something goes wrong

If you see an error while running or submitting code, or anything else looks broken, contact your TA. Screenshotting the error message helps them figure out what happened.