#!/usr/local/bin/perl -wT
use CGI qw(:standard);
use strict;

my $num = param('number');  #has to be numeric
my $let = param('lets'); #has to be letters
my $both = param('both'); #can be letter or number
die "Invalid datatype for num" if $num =~ /[^0-9]/;
die "Invalid datatype for let" if $let =~ /[^a-zA-Z]/;
die "Invalid datatype for both" if $both =~ /[^0-9a-zA-Z]/;
die "num can not be null" unless defined $num;
die "let can not be null" unless defined $let;
die "both can not be null" unless defined $both;