1 files changed, 24 insertions, 0 deletions
diff --git a/013/ch1.pl b/013/ch1.pl
new file mode 100755
index 0000000..4a436cb
--- /dev/null
+++ b/013/ch1.pl
@@ -0,0 +1,24 @@
+#!/usr/bin/env perl
+#
+# Write a script to print the date of last Friday of every month of a given year
+################################################################################
+
+use strict;
+use warnings;
+
+use Time::Local qw<timelocal>;
+
+die "Usage: $0 <year>\n" unless @ARGV == 1;
+my $year = shift;
+
+my %last_dom = (
+    0 => 31, 1 => 28, 2 => 31, 3 => 30, 4 => 31, 5 => 30,
+    6 => 31, 7 => 31, 8 => 30, 9 => 31, 10 => 30, 11 => 31
+    );
+
+foreach my $month (0..11) {
+    my $last_day = $last_dom{$month};
+    my $last_wday = (localtime timelocal(0, 0, 0, $last_day, $month, $year))[6];
+    my $last_friday = $last_day - $last_wday + ($last_wday >= 5 ? 5 : -2);
+    printf "%d/%02d/%d\n", $year, $month+1, $last_friday;
+}