use strict;
use warnings;
use Time::Local;
my @day_Of_Month = ( 5, 16, 20 );
#i want to use this array one by one to do unix time stamp

use Time::Piece;
my $t = localtime($^T);
printf "entire time:  %s\n", $t;
printf "Month: %s\n",        $t->month;
printf "Year:  %s\n",        $t->year;

for my $dayOfMonth (@day_Of_Month) {
    my $updatetime = timegm(59,59,23,$dayOfMonth, $t->_mon, $t->year);
    printf "time for %2d  %d  (%s)\n", $dayOfMonth, $updatetime,
      scalar gmtime($updatetime);
}

#time for  5  1391644799  (Wed Feb  5 23:59:59 2014)
#time for 16  1392595199  (Sun Feb 16 23:59:59 2014)
#time for 20  1392940799  (Thu Feb 20 23:59:59 2014)