Answer to Scripting Programming tutorial 2, question 2

tutorial2-q2.pl

#!/usr/bin/env perl

use strict;
use warnings;
use utf8;

=pod

=head1 Tutorial 2: Question 2

Write a Perl script to calculate the day of a given date (assuming the same
month). It randomly generates a date between 1-7 as the first Monday of
the month (using the rand function).

=over 4

=item 1.

If the user enters a date between 1-28, then the script will print out the
day.

=item 2.

If the date is in between 29-31, the corresponding day will still be
printed but with a warning such as "that date might not be valid in the
current month".

=item 3.

If the given number is larger than 31 or less than 1 an error will be
printed.

=back

=cut

#my $firstMonday = 5; # march 2018
my $firstMonday = 1 + int(rand(7));

my @days = (
	"Monday", "Tuesday", "Wednesday", "Thursday",
	"Friday", "Saturday", "Sunday"
);

my $date = shift;

if ($date < 1 || $date > 31) {
	print "error: date out of bounds\n";
	exit 1;
}

if ($date > 28) {
	print "warning: that date might not be valid in the current month!\n";
}

print $days[ ($date - $firstMonday) % 7 ] . "\n";