#!/usr/bin/perl -w

use strict;
use warnings;
use Calendar::Simple;

my @months = qw(January February March April May June July August
                September October November December);

my $mon = shift || (localtime)[4] + 1;
my $yr  = shift || (localtime)[5] + 1900;
my $sd  = shift;
$sd = 1 unless defined $sd;

my @month = calendar($mon, $yr, $sd);
my $mon_name = $months[$mon - 1];
my $pad = int((20 - length("$mon_name $yr")) / 2);
print "\n", ' ' x $pad, "$months[$mon - 1] $yr\n";

my @days = qw(Su Mo Tu We Th Fr Sa);
push @days, splice @days, 0, $sd;
print "@days\n";

foreach (@month) {
  print map { $_ ? sprintf "%2d ", $_ : '   ' } @$_;
  print "\n";
}
