## WeBWorK Problems

### Solution with multiple cases ### Solution with multiple cases

by Siman Wong -
Number of replies: 2
I'm authoring a webwork problem whose solution key (i.e. the one seen by students) depends on the randomized parameter. I tried
to do that using if/then/else (see below) but GPLab gives the error

Can't find string terminator "END_SOLUTION" anywhere before EOF at (eval 2048) line 77.

I'd be most appreciative for any advice and suggestions. THANKS!

#Context()->texStrings;

if($m % 2 == 0){ SOLUTION(EV3(<<'END_SOLUTION'));$PAR SOLUTION $PAR (text of first case) END_SOLUTION } else{ SOLUTION(EV3(<<'END_SOLUTION'));$PAR SOLUTION $PAR (text of second case) END_SOLUTION } #Context()->normalStrings; In reply to Siman Wong ### Re: Solution with multiple cases by Paul Pearson - Hi Siman, For some reason, Perl and / or WebWork does not like the construction if ($m %2 == 0). If you precompute the modular arithmetic $m % 2, then you should be able to get things to work as expected:$m = random(1,10,1);
$m2 =$m % 2;
if ($m2 == 0) { TEXT("$m even");
} else {
TEXT("\$m odd");
}

Good luck!

Paul Pearson ### Re: Solution with multiple cases

by Djun Kim -
Hi Siman,

good to hear from you and to see you using WeBWorK.

The error message which you quote is often generated when the
line containing the intended end quote text (in this case "END_SOLUTION")
actually contains  other characters (leading or trailing tabs and spaces are
the usual offenders).

As a matter of style, saying

BEGIN_SOLUTION

in place of

SOLUTION(EV3(<<'END_SOLUTION'));

is a nice bit of syntactic sugar which makes problems a little easier to read.

Cheers, Djun