** Using WeBWorK **

Has anyone managed to make decent truth-table questions in WK? I'd like, if possible, an actual table, like this:

p | q | pto q ------------

T | T | ???? ------------

T | F | ???? ------------

F | T | ???? ------------

F | F | ????

where the ???? is replaced either by ans_rules or, even better, HTML choose-lists.

If you know a solution, please email it to me at scorwin@radford.edu.

Thanks in advance,

Steve

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Okay, I found the begintable() sub, and I got the solution below, but it prints a column of zeros before printing the table. Anyone know why, and what to do about it?

Thanks,

Steve =============================================

# initialize
DOCUMENT();

loadMacros(PG.pl,
PGbasicmacros.pl,
PGchoicemacros.pl,
PGanswermacros.pl,
PGauxiliaryFunctions.pl,
PGgraphmacros.pl);

# Do NOT show partial correct answers
$showPartialCorrectAnswers = 0;

TEXT(beginproblem());

BEGIN_TEXT
$PAR
Complete the following truth table.$BR
\{begintable(3)\}
\{row("\\(p\\)","\\(q\\)","\\(p\\to q\\)")\}
\{row("\\(T\\)","\\(T\\)",ans_rule(1))\}
\{ANS(str_cmp("T"));\}
\{row("\\(T\\)","\\(F\\)",ans_rule(1))\}
\{ANS(str_cmp("F"));\}
\{row("\\(F\\)","\\(T\\)",ans_rule(1))\}
\{ANS(str_cmp("T"));\}
\{row("\\(F\\)","\\(F\\)",ans_rule(1))\}
\{ANS(str_cmp("T"));\}

\{endtable\}
$PAR
END_TEXT

ENDDOCUMENT();

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The zero's are coming from the lines \{ANS(str_cmp("T"));\}. (This becomes clearer if you look directly at the source of the HTML -- one of many tricks for trouble shooting these problems.)

You can fix this in at least two ways:

Use \{ANS(str_cmp("T"));""; \}

The output from the second statement, which is an empty string, is the result of the evaluation instead of the 0, which is the result of the ANS function.

Alternatively you can simply collect the ANS() statements and execute them outside of the BEGIN_TEXT/END_TEXT block. (They need to be executed in the same order as the ans_rule statement, but not necessarily immediately after the ans_rule is printed.)

ANS wasn't originally originally conceived as being executed within TEXT blocks. It's possible that we could correct this "bug/feature" in ANS by insuring that it's output is always an empty string. I'll have to look into the ramifications of that.

Thanks for the alert about this "bug/feature".

--Mike

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Arnie

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