Hello Perl language learners, school/college students here is another interesting program that will help you to understand the basic concepts of Perl CGI Web scripting such as how to get a value from the input, How to print a value etc.,
In this post, we are going to write a simple Perl program to find the entered number is a Prime number or not!
Let’s write the Perl Script:
#!/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 number for the input box
my $default_num = 96;
## change the default year to the last entered year
$default_num = param("num") if request_method() eq "POST";
##HTML Part
print "<html>
<head><title>Perl CGI Script to find primer number or not!</title></head>
<body>
<h3>Web Based Perl script to Find Primer number or not - <a href='http://www.tutorialsmade.com/'>Tutorialsmade.com</a></h3>
<form action='' method='post'>
<label>Enter a number <label>
<input type='number' value='".$default_num."' name='num' />
<input type='submit' value='Submit' />
</form>
</body>
</html>";
## here is the perl logic starts
my $q = new CGI;
my $c = 0;
## check if a form is submitted with $q->param()
if($q->param())
{
## get the year from the input
$num = lc($q->param('num'));
## loop till i equals to num
for ($i = 1; $i <= $num; $i++) {
## check if the num is divisible by itself and 1
## % modules will give the reminder value, so if the reminder is 0 then it is divisible
if ($num % $i == 0) {
## increment the value of c
$c++;
}
}
## if the value of c is 2 then it is a prime number
## because a prime number should be exactly divisible by 2 times only (itself and 1)
if ($c == 2) {
printf("<p style='color: green'> %d is a prime number </p>", $num);
}else{
printf("<p style='color: red'> %d is not a prime number </p>", $num);
}
}
Read the comments in the above program to understand it.
You can see the live demo of the above Perl Script below:
Enjoy learning. Good luck!