use strict;
use warnings;
use IO::Socket;

## Some Main Stuffs Here

## Get port numbers
&get_input();

## Few Remaing stuffs Here

sub get_input
{
        my $default_port = "10001";
        print "\nPlease Enter the Port Number  [ Default $default_port ] : ";
        chomp(my $get_port_no=<>);
        $get_port_no=($get_port_no)?$get_port_no : $default_port;
        my $free_port = check_port($get_port_no);
        print "\nFree port is : $free_port\n";
}

## Validate the prompted port number
sub check_port
{
        my ($port)=@_;
        my $host='127.0.0.1';

        my $socket = new IO::Socket::INET(PeerAddr => $host.":".$port, Timeout => 5);

        if ($socket) {
                print "\nPort $port connected successully\n";
                return $port;
        }
        else {
                print "Port $port is currently used by another application\nPlease try again\n";
                &get_input();
        }
}