[system] / trunk / pg / macros / contextIntegerFunctions.pl Repository:
ViewVC logotype

View of /trunk/pg/macros/contextIntegerFunctions.pl

Parent Directory Parent Directory | Revision Log Revision Log


Revision 5441 - (download) (as text) (annotate)
Tue Aug 28 22:40:15 2007 UTC (12 years, 5 months ago) by dpvc
File size: 1675 byte(s)
Add context names for the context(s) created here.

    1 loadMacros('MathObjects.pl');
    2 
    3 sub _contextIntegerFunctions_init {context::IntegerFunctions2::Init()}; # don't reload this file
    4 
    5 =head3 Context("IntegerFunctions")
    6 
    7  ######################################################################
    8  #
    9  #  This is a Parser context that adds integer related functions C(n,r)
   10  #  and P(n,r).  They can be used by the problem author and also by
   11  #  students if the answer checking is done by Parser.  The latter is
   12  #  the main purpose of this file.
   13  #
   14  #  Note: by default, webwork problems do not permit students to use
   15  #        C(n,r) and P(n,r) functions.  Problems which do permit this
   16  #        should alert the student in their text.
   17  #
   18  #  Usage examples:
   19  #     $b = random(2, 5); $a = $b+random(0, 5);
   20  #     $c = C($a, $b);
   21  #     ANS(Compute("P($a, $b)")->cmp);
   22  #
   23  #  Note: If the context is set to something else, such as Numeric, it
   24  #        can be set back with Context("IntegerFunctions").
   25 
   26 =cut
   27 
   28 package context::IntegerFunction2;
   29 our @ISA = qw(Parser::Function::numeric2); # checks for 2 numeric inputs
   30 
   31 sub C {
   32   shift; my ($n,$r) = @_; my $C = 1;
   33   return (0) if($r>$n);
   34   $r = $n-$r if ($r > $n-$r); # find the smaller of the two
   35   for (1..$r) {$C = ($C*($n-$_+1))/$_}
   36   return $C
   37 }
   38 
   39 sub P {
   40   shift; my ($n,$r) = @_; my $P = 1;
   41   return (0) if($r>$n);
   42   for (1..$r) {$P *= ($n-$_+1)}
   43   return $P
   44 }
   45 
   46 sub Init {
   47   my $context = $main::context{IntegerFunctions} = Parser::Context->getCopy("Numeric");
   48   $context->{name} = "IntegerFunctions";
   49 
   50   $context->functions->add(
   51     C => {class => 'context::IntegerFunction2'},
   52     P => {class => 'context::IntegerFunction2'},
   53   );
   54 
   55   main::Context("IntegerFunctions");
   56 }
   57 
   58 1;

aubreyja at gmail dot com
ViewVC Help
Powered by ViewVC 1.0.9