Check for valid Date

				
=**************************************
= Name: Check for valid Date
= Description:This subroutine simply checks if a given date is valid. It also takes leap years into account. Please rate my code.
= By: sp
=
= Inputs:$datein -> Required string containing a date in "dd/mm/yyyy" format
=
= Returns:1 # date okay
-1 # day invalid
-2 # month invalid
-3 # year invalid
=
=This code is copyrighted and has= limited warranties.Please see http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=240&lngWId=6=for details.=**************************************

##################################################
#
# This subroutine simply checks if a date is valid
# Usage: if (&isdate($datein)) { print "ok!" ; }
# $datein -> Required - "dd/mm/yyyy" format
# Returns: 1 # date okay
#	-1 # day invalid
#	-2 # month invalid
#	-3 # year invalid
#
##################################
sub isDate {
 my ($dd,$mm,$yy) = split(/\//,@_[0]) ;
 # make sure that $yy is 4 digits
 if ($yy =~ /^\d\d$/) {
if ($yy < 70) {
 # will assume after 70 is in the 1900's
 #u can change this... 
 $yy += 2000 ;
} else {
 $yy += 1900 ;
}
 }
 @monthDays = (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31) ;
 # check for leap year - Thanks Megan :-)
 if ($yy == int($yy/400)*400) {
$monthDays[1] = 29;
 } elsif ($yy != int($yy/100)*100) {
if ($yy == int($yy/4)*4) {
 $monthDays[1] = 29;
}
 }
 return -3 if ($yy !~ /^\d+$/) ;
 return -2 if (!(($mm > 0) && ($mm <= 12))) ;
 return -1 if (!(($dd > 0) && ($dd <= $monthDays[$mm-1]))) ;
 return 1 ;
}