Web Based Perl script to Find Factorial of a Number!

This is a basic Web-based Perl Script that helps school and college students to improve their knowledge in Perl Scripting.

If you don’t know what is factorial, here is a small explanation,

Multiplying the given integer with the sequence of descending positive integers is called factorial.  For example,

5! is 5 x 4 x 3 x 2 x 1 = 120
So the value of 5! is 120

We can also find the values the other way around ie.,
5! is 1 x 2 x 3 x 4 x 5 = 120

In this program, we are going to follow the above second method to find the value of the n! (n factorial)

Now, let’s see the Perl Script here:

#!/usr/bin/perl -w
##these two lines are used to display errors on browser. If you don't want, you can remove these
use CGI;
use CGI::Carp qw(warningsToBrowser fatalsToBrowser);
##error display ends
 
##below line is important if you want to display the result in browser
print "Content-type: text/html\n\n";

##HTML Part
print "<html>
<head><title>Perl CGI Script to find Factorial of a Number</title></head>
<body>
    <h3>Web Based Perl script to Find Factorial of a Number - <a href='http://www.tutorialsmade.com/'>Tutorialsmade.com</a></h3>
	<form action='' method='post'>
        <label>Enter Number to calculate Factorial <label>
        <input type='text' name='number' />
        <input type='submit' value='Submit' />
    </form>
</body>
</html>";


## here is the perl logic starts
my $q = new CGI;
## check if a form is submitted with $q->param()
if($q->param())
{
	##get the param
	$number = $q->param('number');
	$fact 	= 1;
	print "<br><br>Factorial of ", $number ," is: <br>";
	##loop till $number is less than equal to $i
	for($i = 1; $i <= $number; $i++)
	{
		$fact = $fact * $i;
		print $fact,"<br>";
	}

}

Just go through the inline comments to understand the script.