COS 126 Programming Assignments, Fall 2001

With the exception of Assignment 0, all assignments are due Wednesday night at 11:59 PM by electronic submission. Before you turn in the assignment, be sure to read the Assignment checklist and carefully follow all instructions.

Any changes or corrections to the assignments will be noted in the course announcements. You are responsible for the information in the (most up to date) electronic version of each assignment. Feel free to look ahead at any future assignments that appear online, but be warned that some changes are possible.

Computer Accounts

Every student enrolled in COS 126 has a computer account on the CIT UNIX machines, known collectively as arizona. This account enables you to use the computers in the Friends Center laboratories and other public computing clusters around campus. It is also needed to electronically submit your files. Your login identification is in the campus telephone directory; your password is your PAC (Phone Access Code) or the last eight digits of your social security number. You are strongly encouraged to change your password.

Computing Laboratories

There are a number of computing facilities located in the Friends Center. There is a Sun workstation lab known as arizona for Unix users in 016, a PC lab for Windows users in 017, and Internet connections if you wish to plug in your laptop. The labs are open 24 hours a day, and are staffed by lab assistants most evenings and weekend afternoons. Here is the lab assistant schedule. The lab assistants should only be asked general computer-related questions (e.g., using and installing software like lcc, Unix basics, PostScript syntax, and C syntax). They will also assist you in debugging your code, assuming you have first made a reasonable effort to identify the bug and isolate the problem. If you have questions regarding the course material or programming assignments, see your preceptor or instructor.

Submitting Programming Assignments

Submit your solutions to the programming assignments electronically via the web site courseinfo.cs.princeton.edu. You will receive an email confirmation for each successful submission. You can resubmit or unsubmit files as needed.

Submit the C source code file, e.g., hello.c, and written documentation in a file named readme. Be sure to include your name and precept number in every file you submit.

The purpose of the readmedocumentation is to help the graders determine how well your code solves the assigned problem. Your grade depends on both the code and its documentation. Computer programs can be incomprehensible, even to the person who wrote it (wait until this happens to you). Your documentation should be a brief narrative (no more than 2 pages) that explains what the various parts of the program do, and how. /u/cs126/examples/readme is an example. We will provide skeleton readme files for each of the assignments. Preparing this documentation needn't take a lot of time, but it should be done with care. Writing good documentation is an acquired skill, whose usefulness you will appreciate more and more as you write and maintain large programs. Your readme file should also describe whatever help (if any) that you received in completing the assignment.

In addition, your code should contain comments and be indented consistently for easy reading, but don't get carried away commenting your code. Don't comment the trivial or obvious; for example,

i = i + 1; /* increment variable i by 1 */

isn't much help. However, at a bare minimum you should provide a comment for each function and a brief description of the purpose of your variables. If you use code from elsewhere, identify it and acknowledge its source in your readme file or in comments. The file pattern.c gives example source code.

Late Assignments

Programming assignments are due at 11:59pm on the date specified. Assignments submitted late will be graded according to the following formula: S = .9 R exp(-t/3), where S is the grade given, R is the grade the work would have gotten if turned in on time and t is the amount of time (in days) the work was late. Thus, the value of a late assignment decays exponentially, with a half-life of just over two days. Examples: work turned in five minutes late gets 89.9% credit, one hour late gets 88.7% credit, six hours late gets 82.8% credit, one day late gets 71.7% credit, three days late gets 33.1%, and one week late gets 8.7%. The date and time of the most recently submitted file is taken as the date and time of the entire assignment. This includes non-program files, including the readme file. Programs that are submitted late may not be graded in a timely fashion. Penalties are waived for unforeseen circumstances, like illness, with an appropriate written excuse. Preceptors may also use their discretion to grant extensions.

It is better to submit an incomplete program than to submit nothing. No additional time will be given for unannounced interruptions in computer service. Don't wait until the last minute to write your programs!

Collaboration Policy

Programming is an individual creative process much like composition. You must reach your own understanding of the problem and discover a path to its solution. During this time, discussions with friends are encouraged. However, when the time comes to write code that solves the problem, such discussions are no longer appropriate - the program must be your own work. If you have a question about how to use some feature of C, UNIX, etc., you can certainly ask your friends or the teaching assistants, but do not, under any circumstances, copy another person's program. Writing code for use by another or using someone else's code in any form is a violation of academic regulations. "Using someone else's code" includes using solutions or partial solutions to assignments provided by commercial web sites, instructors, preceptors, teaching assistants, friends, or students from any previous offering of this course or any other course.

You may, however, use any code from the COS 126 lectures, precepts, or course texts, providing that you explain what code you use, and cite its source in your readme file or in comments. An example citation appears in /u/cs126/examples/pattern.c and in /u/cs126/examples/random.c. For each assignment, you must also specifically describe whatever help (if any) that you received from others in your readme file, and write the names of any individuals with whom you collaborated. This includes help from friends, classmates, lab TA's, and COS 126 staff members.

If you have a question about what is fair and what is not, please consult a staff member. Violators will be referred to the disciplinary committee for review. Page 71 of Rights, Rules, Responsibilities asserts:

The only adequate defense for a student accused of an academic violation is that the work in question does not, in fact, constitute a violation. Neither the defense that the student was ignorant of the regulations concerning academic violations nor the defense that the student was under pressure at the time the violation was committed is considered an adequate defense.

Do Yalies need to plagiarise our Collaboration Policy? You be the judge. :)

Protect Your Files

You are responsible for keeping your solutions to the COS 126 programming assignments away from prying eyes. If someone else copies your program, we have no way to determine who's the owner and who's the copier; the Discipline Committee gets to decide. If you are working on a public cluster machine, be sure to delete your source files before leaving.