Random Numbers in Questions

#!/usr/local/bin/perl -- -*- C -*-
use CGI;
srand();
$quest = 10.0*rand();#CREATE RANDOM VALUES
$quest = int(1000*$quest)/1000;#ROUND APPROPRIATELY
$query = new CGI;

print $query->header;
print $query->start_html("q2_rand.pl, Numerical Input Example");
print $query->start_form;

if($query->param('quest') eq ""){$query->param('quest',$quest);}
#IF THIS IS THE FIRST TIME, ASSIGN TO HIDDEN
print $query->hidden('quest');#THEN HIDE IT

$quest = $query->param('quest');#RETREIVE IT
print <<EOF;
<P> How many feet are there in $quest miles?
EOF

$ans = 5280*$quest;

print $query->textfield('stu_ans','',10,30);
print "<P> Is the above answer correct?",$query->submit("Send Answer in For Grading");
print $query->reset;
$quest_x = $query->param('quest');
print $query->end_form;


$returned_ans = $query->param('stu_ans');
if ( $query->param('stu_ans') ne '')
{
	print "<em>Student_answer, </em>$returned_ans";
	$returned_ans =~ s/\//gi; 
	$returned_ans =~ s/\$//gi; 
	$returned_ans =~ s/#//gi; 
	$returned_ans =~ s/~//gi;
	$stu_ans = eval($returned_ans);
print "<br> student answer = ",$stu_ans;
print "<br>, and ans = ",$ans;
$criterion = ($stu_ans - $ans)**2;
print "<br> criterion = ",$criterion;

	if ( (($stu_ans - $ans)**2  ) >= 0.01 ) 
		{print "<em>, was WRONG!</EM>
		<IMG SRC=../icons/checkno.gif>"}
		 else {print "<em>, was RIGHT! </EM>
		<IMG SRC=../icons/check.gif>"};
};
print $query->end_html;

There are two points to make here. The first is the rounding of the random number. The code:

$quest = 10.0*rand();#CREATE RANDOM VALUES
$quest = int(1000*$quest)/1000;#ROUND APPROPRIATELY

The second hard point is the hidden fields problem. We need to know whether or not this particular Perl program has been called before, and to do that we check whether or not the hidden field has a value. If it doesn't have a value, then this is the first time that the Perl program has been called, and we need to assign a value to the hidden field. The line:

if($query->param('quest') eq ""){$query->param('quest',$quest);}

print $query->hidden('quest');#THEN HIDE IT

$quest = $query->param('quest');#RETREIVE IT

That's all there is, there isn't any more, Doc.