Perl web script to find leap year or not

Let’s write a simple Perl program to find leap year, very useful for beginners and school / college students,

Formula for finding a Leap year is as follows:

1. A year should be evenly divisible by 4 (should not have a reminder):

    year % 4 == 0 ( reminder should be 0 )

2. AND Year should not be evenly divisible by 100 (should have a reminder):

    year % 100 != 0 ( reminder should not be 0 )

3. OR Year should be evenly divisible by 400 (should have a reminder):

    year%400 == 0 ( reminder should be 0 )

So basically 1 && 2 || 3

if (1  and 2) both are true or 3 is true then it is a leap year

Here is the Perl web cgi script to find the leap year:

#!/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);
use CGI ":standard";
##error display ends
 
##below line is important if you want to display the result in browser
print "Content-type: text/html\n\n";

## set the default year for the input box 
my $default_year = 1996;
## change the default year to the last entered year
$default_year = param("year") if request_method() eq "POST";

##HTML Part
print "<html>
<head><title>Perl CGI Script to find leap or not!</title></head>
<body>
    <h3>Web Based Perl script to Find Leap year or not - <a href='http://www.tutorialsmade.com/'>Tutorialsmade.com</a></h3>
	<form action='' method='post'>
        <label>Enter the year <label>
        <input type='number' value='".$default_year."' name='year' />
        <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 year from the input
	$year = lc($q->param('year'));
	
	## check if the input year is leap year or not and print accordingly
	if ((0 == $year % 4) && (0 != $year % 100) || (0 == $year % 400)) {
		print "<p><span style='color:green; font-weight:bold;'>". $year ." is a Leap Year!</span></p>";	
	}else{
		print "<p><span style='color:red; font-weight:bold;'>". $year ." is not a Leap Year!</span></p>";	
	}
}
 

The code is self-explanatory, read the comments in the script to understand it well.

Here is the live demo of this script:

Enjoy learning. Good luck!