Compare two dates

				
=**************************************
= Name: Compare two dates
= Description:This routine compares two dates and returns a number indicating how the first date compares to the second (greater than, less than, or equal to).
= By: John Winger
=
= Inputs:It takes two arguments: two dates formatted like YYYY-MM-DD[ hh:mm:ss] (like from MySQL for instance).
=
= Returns:The routine returns -1 if date1 is less than date2, 1 if date1 is greater than date2, or 0 if they are equal.
=
= Assumes:If the two dates contain different amounts of information (like one includes the time and the other doesn't) then they are compared up to the lesser amount of info.
=
=This code is copyrighted and has= limited warranties.Please see http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=324&lngWId=6=for details.=**************************************

##
## Written by John Winger (john@wingeronline.com)
##
## Use as you wish, but as a courtesy I ask that you give me credit in your code. 
##
print "This script is testing a routine to compare 2 dates.\n\n";
$dtcompare = "2002-03-04 14:36:15";
print "Enter a date to compare against $dtcompare: ";
$userdate = <STDIN>;
chomp($userdate);
$comp_results = compareDbDateTime($userdate, $dtcompare);
if($comp_results == -1) { print "\t$userdate is less than $dtcompare\n\n"}
elsif ($comp_results == 0) { print "\t$userdate is equal to $dtcompare\n\n" }
elsif ($comp_results == 1) { print "\t$userdate is greater than $dtcompare\n\n" }
else{ print "\tError\n\n"}
sub compareDbDateTime
{
	# answers how does date1 compare to date2
	# (greater than "1", less than "-1", or equal to "0")
	my ($dt1, $dt2) = @_;
	
	my @datetime1;
	my @datetime2;
	my $limit = 0;
	
	my ($date1, $time1) = split(/ /, $dt1);
	push(@datetime1, split(/-/, $date1));
	push(@datetime1, split(/:/, $time1));
	
	my ($date2, $time2) = split(/ /, $dt2);
	push(@datetime2, split(/-/, $date2));
	push(@datetime2, split(/:/, $time2));
	
	# compare up to the lesser number of elements
	# (like if one datetime only has a date and no time, don't try to compare time)
	if(@datetime1 == @datetime2) { $limit = @datetime1 }
	elsif (@datetime1 > @datetime2) { $limit = @datetime2 }
	elsif (@datetime1 < @datetime2) { $limit = @datetime1 }
	
	for (my $i = 0; $i < $limit; $i++)
	{
		if ($datetime1[$i] > $datetime2[$i]) { return 1; last; }# date1 greater than date2
		if ($datetime1[$i] < $datetime2[$i]) { return -1; last; }# date1 less than date2
	}
	return 0;# dates are equal
}