COS 126 Programming Assignments, Spring 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.

CS 101 Lab

The CS101 lab is public lab containing Unix machines on the arizona network. It is always open, and is 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., basics of Unix, PostScript, and C). 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 using the command

/u/cs126/bin/submit126 number files

number is the assignment number and files is the list of files for that assignment. For example,

/u/cs126/bin/submit126 0 readme hello.c

submits the files readme and hello.c for assignment 0.

The submit command copies your files to the directory /u/cs126/submit/login/number, and lists all the files that you have submitted for assignment number. If you execute submit after the assignment deadline, you will receive a warning message verifying your actions. If you proceed, your assignment will be marked as late. You can run submit more than once, and you can submit partial lists of files.

What to Submit

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 documentation 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. 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.

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. If you use code from elsewhere, identify it and acknowledge its source in your readme file or in comments. Also describe whatever help (if any) that you received in completing the assignment.

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 program. 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 only for unforeseen circumstances, like illness, and then only with an appropriate written excuse.

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!

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. :)

Unix 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 of the computers in Rooms 101 in the Computer Science Bldg., and those in other public computing clusters around campus. 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 can change your password by typing passwd and following instructions. Change it regularly.