**LearnCS!** is a pedagogical programming environment designed specifically for use by first-year computer science students. It eliminates, at the course outset, the need for students to worry about text editors or IDEs, Linux commands, and compiling. **LearnCS!** instead provides a web-based environment, immediately accessible, for them to write, run, and debug programs, using an already-familiar browser-based interface. **LearnCS!** has an embedded C interpreter (that runs in the browser), which allows the student to simply click the Run button and obtain immediate results. Many common syntactical errors yield hints to the student of the likely cause of their problem. When students use **LearnCS!**, the code editor allows setting breakpoints, and the student may then step through the program. A depiction of memory is provided to the students, where they can see, in detail, the state of their program as they step through it. When they call functions, students learn how arguments and return locations are pushed onto the stack and memory for automatic local variables is reserved. They see a visualization that assists them in building a mental model of the underlying notional machine.

In addition to its direct benefits for students, LearnCS! is designed as a research platform for studying how novices learn to program. Snapshots of student progress are automatically saved on the LearnCS! server. Student activity, such as running the program, operations of the debugger (setting or clearing a breakpoint, stepping through the program, etc.), and opening or closing the memory depiction are also stored.

Installation

The following steps will install a working version of LearnCS!.

1. Create a virtual machine and install 64-bit Kubuntu 14.04 Linux. ( LearnCS! has been shown to work well on 64-bit Kubuntu 14.04. It has not been tested on most other distributions. A hard requirement, for use with the node modules in this git repository, is 64-bit.)

2. Ensure that required packages are installed

   apt-get install git sqlite3 nodejs

3. Obtain LearnCS!

   git clone https://github.com/derrell/LearnCS.git LearnCS.git

4. **LearnCS!** uses some libraries that have their own git repositories. These are called "submodules." Retrieve the code for the submodules. This will take a few minutes.

   cd LearnCS.git; git submodule init; git submodule update

5. Build the C interpreter.

   cd desktop/compilers/ansic; make

6. There are a number of programs and tests that are used to verify that the interpreter is working properly. Run those tests.

   cd canning; ./dotests.sh

7. Create the LearnCS! configuration file. This file is in a directory called private, at the top level.

   cd ../../../..
   mkdir private
   cp learncs-config-TEMPLATE.json private/learncs-config.json
   

8. Edit your private configuration file, as required for your site.

• url: The URL which your users will use to access LearnCS! . This URL will be used in the link emailed to registering users.

• notifyRecipients: a comma-separated list of email addresses to whom notifications will be sent to notify them of user registrations. (Notice that in the template configuration file, there is a leading X, changing the configuration key from notifyRecipients to XnotifyRecipients. The leading X comments out this entry, so notifications are not sent to anyone. If you wish to have notifications sent, remove the leading X.)

• email: The entries inside of the braces provide the information necessary for contacting your outbound SMTP mail server. This is how LearnCS! will send registration links to registering users.

1. The graphical user interface and backend server are built via a single command, from the backend directory. Change into that directory.

   cd backend-nodesqlite

2. Build the frontend GUI and the backend server.

   ./generate.py build

3. Add a few template programs that will be available to all users.

   tar -xvzf USERCODE-initial.tgz

4. Change into the deploy directory, from which LearnCS! is run.

   cd deploy

5. Start the LearnCS! server. Note that HTTPS is disabled (by setting its port to 0) because these installation steps do not cover how to create (self-signed or otherwise) HTTPS keys/certificates.

   nodejs ./backend.js http.port=8080 https.port=0 &

6. Create your primary (initial) user account. (Additional accounts are created via the Create a new account button in the user interface. Be sure to test that, later, to ensure that your email configuration is correct.)

   nodejs newuser.js <your_email_address> <password>, "<full_name>"

7. Connect to LearnCS! using the Chrome browser, at http://YOUR_SERVER_NAME_OR_IP:8080/

8. Click the botton at the bottom of the page, to create a new account. Follow the instructions.

9. Create your course. (This currently requires a bit of SQL entry in the database. Contact me for assistance.)

10. Enjoy!