CloudCoder is a web-based programming exercise system. We will be using it for practice problems to accompany the reading assignments. By doing the CloudCoder practice problems, you can test your understanding of the material covered in the reading.

Note: CloudCoder is somewhat experimental. If you encounter any problems, please email Prof. Hovemeyer at

Getting Started

In a web browser, visit the URL

Log in using your Marmoset username and password.

You will see a window that looks like the following one (click for full size):

Expand Spring 2012, and select CS 101. Then click on the a problem in the table at the top of the page. The page should now look like this (in this example, I clicked on the addInts problem):

Click the Load problem! button. You will now see a page that looks like this:

Working on a problem

Your task is described in the problem description at the top left of the window. Enter your code in the text editor (the section of the window with the black background.)

To test your program to see if it correctly solves the problem, click the Submit! button.

If your solution is correct, all of the items in the Test results tab will be marked as passed:

If your solution has a bug, one of more of the tests will not be marked as passed:

If your tests do not pass, or if your program does not compile successfully, check the Compiler errors tab: