#! /usr/bin/perl -w
use strict;
print "Enter numeric:  day  month  year\n";
my ( $day, $month, $year ) = split ' ', <STDIN>;
print "day=$day, month=$month, year=$year\n";
my @days = ( 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 );
--$month >= 0 or die "bad date\n";
$day > 0 and $days[$month] and $day <= $days[$month] or die "bad date\n";
print "good date\n";