Computer Science 60
Principles of Computer Science
Assignments/Grading Policies, Fall 2000

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Assignments

Notes on Code Formatting and Commenting

Worksheets

Assignment Policy

    What, Friday?!

Acknowledging the demands of other classes, CS60 has an automatic two-day extension available on each assignment. Assignments submitted within the two-day extension (by Sun. midnight) will be graded for full credit; those submitted between midnight and 2:00 pm on the Monday after will lose half credit; later assignments will not receive credit. (We start posting solutions.) That's not to say they're not worth doing, of course!

Where are the machines?

Room 102 Beckman is where the X terminals connected to our server turing are. If you don't wish to use an X terminal, you may use a secure protocol (e.g., ssh, SecureCRT, FSecure) to get to turing.cs.hmc.edu. You may check out a CD from the Computer Science office (Olin 1240, 1-5pm) to copy FSecure onto your computer (both Windows and Mac versions are on the CD; if you run linux, you already have ssh). Getting acquainted with turing is a good idea, since some software we use will not be available on other machines. Because FSecure will be in demand, you can download and use (for free) a trial version of SecureCRT for about a month. It's available from www.vandyke.com/products/securecrt/ .

Getting Help

You will get an account on turing. In your home directory you should have a directory named cs60, whose group owner is cs60. If not, the system administrator will create one for you. Access to this directory will thus be by you, the instructor, and the tutors, but preferably no one else. When properly setup, the directory listing is obtained by ls -l and should look like this:

 
    drwxrwx--- 2 yourid cs60  512 Sep 8 20:32 cs60/ 

%  chmod 770 cs60

Your cs60 directory lets us help you on problems with code without your having to mail the code. You will need to change the permissions of the file you'd like the instructor or tutor to read. To do this, type

%  chmod 644 <filename>

Submitting Assignments

where <assignment #> is the number of the assignment being submitted. The file should be an text file, that is, it should be source code. It's important that the file be named as specified in the assignment, e.g., hw1.rex.

When you use cs60submit, your submission is partially graded on the spot and will return a score of how you did. This feature is intended to make it easy to catch problems like typos that cause your submission to fail completely. In addition, you know for sure that you will receive those points on the assignment. Keep in mind that there are other tests -- and style guideines -- that your code will be run against.

It is a good idea to keep your files to widths of less than 80 characters (it makes them easier to read and grade). All submissions are kept for archival purposes, but only the latest submission before the time deadline will be graded.

Mail on Turing

To you have your mail on turing forwarded to another machine, create a file named .forward in your top-level directory. (Yes, there's a dot in front of the file name. To see such files, type ls -a.)

In your .forward file, put the address to which you'd like the mail to be forwarded on the first line. If you want it forwarded and also wish to retain a copy on turing, include immediately after that address and on the same line:

    ,\yourUsername

Assignment Grading

The assignments will stress programming, though there may also be some paper-and-pencil exercises. Programming assignments help drive home key working concepts and principles. Assignments vary in difficulty and may not be equally weighted. Sufficient information about the programming languages you will be using will be provided in class with some reinforcement in the assignment descirptions themselves. There are considerable online resources for those languages, too, on the references page. You do not have to know these languages when you enter the class. You should, however, have some background in an imperative language such as Java, C++, or Pascal.

Each assignment will be worth 50 points. Partial credit will be given and extra credit (usually 20%) is available. 10 points of each assignment depends on the legibility and commenting of your code --- basically for "good coding style." The following list describes what we expect in terms of coding style. These are worth 2 points each.

• Use of indenting and consistent indenting. Choose an indenting style and stick with it. There will be lots of example code to suggest readable styles.
• Variable names should be balanced between easy to use (short) and easy to understand (descriptive). If you like using one-letter names, be sure to comment what they are! (except for idioms like loop indices).
• Use of whitespace. Code without sufficient whitespace to indicate its high-level structure can become very hard to read. Use liberally.
• Header comments. Be sure to have your name, the file name, the date, assignment number, and any other information you feel might be useful at the head of your assignment files.
• Comments. You should comment each function you write with its purpose. If you have created an unusual implementation, you should also indicate how (in addition to what) you've coded. This comment should be before the function itself. Within your code, you should add comments to describe at a high-level what is going on. These inner comments need not be everywhere, but enough should be included to get the general sense of how your code works.

Programs which do not compile and run will not receive any points (not even style points!) You will see this when you submit, but keep it in mind. A good idea (in any computer endeavor) is to keep the best working copy of code somewhere safe and alter a different version as you improve things. The best strategy is to progress from a partial, but working, solution toward a final, complete solution by gradually adding features.

Remember, you can always ask about things before you submit your actual product. There is no reason to lose points on most of the above. You also lose no points or esteem for asking.

Course Grading