use strict;

use Date::Calc qw(This_Year Week_of_Year);

my @month_max_days = (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
my $this_year = This_Year();

sub is_leapyear
{
   my ($year) = @_;
   if(!$year)  { return "-1" }
   if($year % 4 == 0)   { $v = 1 }
   if($year % 100 == 0) { $v = 0 }
   if($year % 400 == 0) { $v = 1 }
   return $v;
}

my $is_leapyear = is_leapyear($this_year);
my %weeks_of_year = ();

for my $month (0 .. scalar(@month_max_days) - 1)
{
   my $week = 0;
   my @dates = ();   
   my $date = "";
   my $max_days = $month_max_days[$month];
   $max_days += 1 if $month == 1 and $is_leapyear;

   for my $day (0 .. $max_days-1)
   {
      ($week, undef) = Week_of_Year($this_year, $month, $day);
      unless(defines $weeks_of_year{$week})
      {
         $weeks_of_year{$week} = [];
      }
      $date = "$this_year.$month.$day";
      push @{$weeks_of_year{$week}}, $date;
   }   
}

print join(", ", @{$weeks_of_year{47}});

use Date::Calc qw(Date_to_Days Add_Delta_Days Monday_of_Week);
# den Montag der Kalenderwoche ermitteln und in Tage seit 01.01.0001 umrechnen
my $monday = Date_to_Days Monday_of_Week 47, 2003;
# die 4 Tage drauf, dann ist Freitag der Woche
my $friday = $monday + 4;
# und alles ausgeben
for ($monday, $friday)
{ # Days_to_Date gibt es nicht, deswegen Add_Delta_Days
  # Add_Delta_Days gibt ($year, $month, $day) zurück, deswegen reverse 
  printf "%02d.%02d.%04d", reverse Add_Delta_Days 1, 1, 1, $_-1;
}