Enter option to be parsed
1. Fiction
2. History
3. Religion


10. Non fiction 

##</code><code>##

Selected Book 2. Options are as follow
1. World History
2. American History
3. Oriental History


10. Indian History

##</code><code>##

use strict;
use warnings;
use Switch;
my $level1;
print "Select options: \n 1 Fiction \n 2 History \n 3 Religion \n";
my $no = getIP('Enter a digit : ', /^\d/);
switch ($no) {
		case 1		{ $level1 = ?? }
		case 2		{ $level1 = ?? }
                case 3		{ $level1 = ?? }
		else		{ $level1= ?? }
		
}
print $level1;


sub getIP {
    print $_[0];
    do {
        $_ = <STDIN>; chomp;
    } while ($_[1] && $_ !~ $_[1]);
    return $_;
}