while ($__month >= 0){
       $days = $days + $monthdays[$__month];
       --$__month;
   }
##</code><code>##

@monthdays = ("0", "31","28","31","30","31","30","31","31","30","31","30","31");
my $days = 0;

while (--$__month >= $[){
    $days = $days + $monthdays[$__month];
    #--$__month;
}
$days = $days + $__day;