Modulus zero error

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Modulus zero error by BrowserUk (Patriarch) on Dec 24, 2004 at 05:13 UTC
Your looking at the wrong line (or being pointed at th wrong one?). The error is in this line: `while ($x % $p[$i] !=0) __________^` [download] Examine what is said, not who speaks. The end of an era! "But you should never overestimate the ingenuity of the sceptics to come up with a counter-argument." -Myles Allen "Think for yourself!" - Abigail "Time is a poor substitute for thought"--theorbtwo "Efficiency is intelligent laziness." -David Dunham "Memory, processor, disk in that order on the hardware side. Algorithm, algorithm, algorithm on the code side." - tachyon	[reply] [d/l]
Re^2: Modulus zero error by Anonymous Monk on Dec 24, 2004 at 05:19 UTC
Yeah... I didn't really understand the line number - it said "line 25, <> line 3." (line 25 is the if statement) And when I truncate line 25, the error stops happening - i don't see how that line can affect the while part, since it's not changing anything..	[reply]
Re^3: Modulus zero error by sasikumar (Monk) on Dec 24, 2004 at 05:46 UTC
Cool The answer is perl has built a hash table in your while statement but when it comes to if it see's $p.. which is a new variable accordint to perl.. So there comes the problem. This is why it states the error in a wrong place Note: Use Strict and warnings Update: OOps sorry i mis understood the problem. Ok The problem lies in this line `if (($n < $p[$i]) && ($x > $p[-1])) # error here` [download] just remove the previous code and use this u will not see the warning. `if (($n < $p[$i]))` [download] This is becasue the lt operator should work by finding the modulus and then determine the solution.(I am not sure with that but for this error i hope this could be the reason. i will update on you again after 15 minutes Sorry i was not able to find it out.... Thanks Sasi Kumar	[reply] [d/l] [select]
Re^4: Modulus zero error by Anonymous Monk on Dec 24, 2004 at 06:29 UTC
Re^5: Modulus zero error by maa (Pilgrim) on Dec 24, 2004 at 07:52 UTC
Some notes below your chosen depth have not been shown here
Re^4: Modulus zero error by ysth (Canon) on Dec 24, 2004 at 05:50 UTC
Re: Modulus zero error by hv (Prior) on Dec 24, 2004 at 12:34 UTC
Some version of perl had problems reporting the correct line number for errors, and it is likely in this case that it is reporting the correct error with the wrong line number. I'd suggest adding diagnostic `warn()` statements throughout the program to pinpoint where it reached just before the error message, or alternatively concentrate on places in the program that the `%` character appears. If you are not using `%` as a modulus operator in your program, it is possible that mismatched quotes or brackets are causing a `%$hashref` to be misinterpreted. Hugo	[reply] [d/l] [select]
Re: Modulus zero error by xdg (Monsignor) on Dec 24, 2004 at 13:42 UTC
I don't think we can give a solid answer without knowing better what @p contains. If @p is empty or is a new variable ("`use strict`"), then the first time through the loop `while ( $x % $p[$i] != 0 )` could report a "use of undefined in modulus" because `$p[$i]` is undefined. -xdg Code posted by xdg on PerlMonks is public domain. It has no warranties, express or implied. Posted code may not have been tested. Use at your own risk.	[reply] [d/l] [select]
Re: Modulus zero error by Anonymous Monk on Dec 24, 2004 at 21:36 UTC
oops... sorry, I think the whole thing was because I'd used the variable $i somewhere else, which screwed everything up heh.	[reply]
Re: Modulus zero error by jalewis2 (Monk) on Dec 25, 2004 at 02:45 UTC
I was just getting this error yesterday and it was making me crazy. I was doing this at the start of my script. `my $x = undef;` Not realizing that the error was telling me $x needs to be something. I changed it from undef to 0 and that fixed it. Thinking back, trying to do the operation on an undefined variable was dumb, but I didn't "see" it.	[reply] [d/l]