I'm forwarding the responses I gave to individuals to the whole group (sorry for the duplicates to the individuals):
===== I don't usually expect the correct answer on that question - I usually feel good about the candidate if they see the problem on paper & put parens in the right places: $> perl -e '$x=1; $y=($x++)+1; print "x=$x, y=$y\n"' This is because '++' has a higher precedence than '+'. It's not so much that I dislike a candidate if they fail to answer it or I want to prove look how cool I am. In fact it's just the opposite: what I'm trying to evaluate is how they react when they find themselves in unfamiliar territory - it's more like testing their attitude to new problems/situations, which could be both technical & non-technical. It's actually more a behavioral interview question rather than a technical one - given that you have to hire someone based on a few minutes of interaction, any insights I can get into their behavior patterns, the better I can assess their fit into our own organization (my point (b) below). ===== > If you're hiring someone to primarily work in perl, then they will > approximately never use a linked list, and whether to use an array or a > hash is determined by the nature of the data access, not by which one > shaves a nano-second off execution time. By answering just the way you have, you have passed the test, since you demonstrated that you understood the underlying issue (execution time) & then made a conscious decision (it doesn't matter in problem X's context). FWIW, the 'nanosecond' might add up depending on the size of the problem you are solving. If you have a problem that has 10 million entities, for example (like I had in one case), the choice of data structures can mean the difference in tens of minutes or hours of run time - & sometimes that matters if you have to run it multiple times across different data sets to compare & contrast - which means the difference between being able to get the answer in 1/2 day or waiting for 2 days to get back to the team with the results. > Remembering the minutiae of operator precedence is not, IMO, a sign that > someone is a good developer. I'd never write anything like that, and if > I came across it while maintaining someone elses code, I'd read perldoc > perlop, write a quick test case, and change it to something that > wouldn't bamboozle the next maintainer. Again, a valid answer! You demonstrate initiative in that you are willing to do the leg work & find solutions yourself instead of waiting for someone else to spoon feed you (as in the prior comparison to the 'Linux box'). > FWIW, I'd have answered x=2, y=2 or 3, and then explain why I don't > think it matters that I can't be sure. y=3 can't happen: there's only 2 ways to break up the '+++': (a) ($x++)+1 (b) $x+(++1) The second one is invalid since you can't increment a constant value: Perl's exact error is: "Can't modify constant item in preincrement" Again, if a person gave me the 2 options and, thinking aloud, went through the both options, I'd get a very good idea of what their approach to problem solving is (break it down to pieces & attack each piece separately, also known as 'divide & conquer') or is not. -Nilanjan -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, March 07, 2005 11:01 AM To: [EMAIL PROTECTED] Cc: [email protected] Subject: RE: [Boston.pm] Perl popularity and interview questions Palit, Nilanjan said: >> ~~$> perl -e '$x=1; $y=$x+++1; print "x=$x, y=$y\n"' >Bummer. I just got a ding on your interview. >How do you parse $x+++1 ? $y=$x+++1 is $x+1 $y=$x $x++ I believe. If that's what you mean by parse. :-) -John ___________________________________________________________ Sent by ePrompter, the premier email notification software. Free download at http://www.ePrompter.com. _______________________________________________ Boston-pm mailing list [email protected] http://mail.pm.org/mailman/listinfo/boston-pm _______________________________________________ Boston-pm mailing list [email protected] http://mail.pm.org/mailman/listinfo/boston-pm
