Perl

All Homeworks and In-Class Assignments have been graded. Please check your grades online, and let me know if there are any problems. Your final letter grade as given on the Check Grades page will be what I submit via SIS later this week.

The HW6 submission script has finally been written. You can submit your homework by running ~lallip/public/hw_submit.pl on solaris.remote.cs.rpi.edu.

Next week's class, October 26, is cancelled. No in-class assignment or lecture will be given that day. The due date of homework four, November 1, is unaffected.

I have just submitted the request to labstaff to have new Computer Science department accounts created for those students who indicated they do not yet have accounts when they signed up for the course. If you signed up indicating you do not know your password, I have requested it be reset. If you indicated you do not know if you have an account, either a new account request or password reset request was submitted for you, based on whether or not you actually have an account.

Sometime in the next week or so, you should get an email to your normal RPI email address regarding your new Computer Science account. It is vital that you follow the instructions contained in this email as quickly as possible. The temporary password that labstaff assigns will expire (I believe within a week of account creation). Every semester, at least two students fail to change their temporary passwords, and then discover they can't log into the CS servers to do their CGI homework (which, of course, they started the night the homework was due). Please do not let yourself be one of these students this semester.

Please note that once you have successfully logged into the CS servers and changed your password, you will not need to use this account again until we do the lessons on CGI programming and Perl/Tk. Please continue to use the RCS (rcs-sun4.rpi.edu) machines for all Perl work until otherwise informed.

It's been brought to my attention that I have made a rather serious goof. I neglected to go over possibly the most important function needed for homework #1.

I will go over the "substr" function now. This function's prototype is as follows: substr(STRING, INDEX, LENGTH)

my $string = "Hello World";
print substr($string, 2, 3);  # 'llo';
print substr($string, 6, 5);  # 'World';
print substr($string, 1);     # 'ello World';
print substr($string, 0, -2); # 'Hello Wor';

As you can see, some extra 'magic' can be applied to the LENGTH argument. If the LENGTH is omitted, substr returns the substring starting at INDEX and going to th end of the string. If the LENGTH is negative, the sub string extends to that many characters before the end of the string.

My profuse apologies for this severe oversight. As a result of this mistake, the deadline for homework #1 has been extended to Friday night at 11:59:59pm. (There will not be any 'late' allowance - anything turned in after Friday at 11:59:59 will be a 0).

If you have any questions about this function, please do not hesitate to ask myself or the TAs.

(If you look at perldoc -f substr, you will see that substr() actually has some additional built in functionality, but it is unneeded for this assignment. We will cover those additions at a later time.)