Two Otober 27, 2002 using timelocal

joe budd has asked for the wisdom of the Perl Monks concerning the following question:

Using the two simple subs below I display each day in 2002. However the date October 27 occurs twice. When I combine the two subs into one, October 27 only comes up once. Any ideas as to why? joe budd

#!/usr/bin/perl

use Time::Local;

&do_year;

sub do_year
{
    my ($i, $date);
    
    for ($i=0; $i<12; $i++)
    {
        $date = timelocal(0, 0, 0, 1, $i, 2002);
        &do_month($date);
    }
}

sub do_month
{
    my ($date_int) = @_;
    my ($month);
    my $day_int = (60 * 60 * 24);
    my @months = ("January", "February", "March", "April", "May", "Jun
+e", "July", "August", "September", "October", "Novenber", "December")
+;
    

    print"\n";
    
    $month = (localtime($date_int))[4];
    while ($month == (localtime($date_int))[4])
    {
        print $months[$month], " ", (localtime($date_int))[3], " ", ((
+localtime($date_int))[5]+1900), "\n";
        $date_int += $day_int;
    }
}
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Comment on Two Otober 27, 2002 using timelocal Download Code

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Re: Two Otober 27, 2002 using timelocal by davorg (Chancellor) on Oct 15, 2001 at 18:54 UTC
That wouldn't be the day that you leave daylight savings time would it? Try it again. but using midday instead of midnight in your call to `timelocal`.	[reply]
Re: Answer: Two Otober 27, 2002 using timelocal by joe budd (Initiate) on Oct 15, 2001 at 21:16 UTC
1) Yes I guess that it is the day we leave daylignt savings time. 2) Midday overcomes that issue. 3) I'm impressed. 4) Thank you.	[reply]
Re: Re: Answer: Two Otober 27, 2002 using timelocal by davorg (Chancellor) on Oct 16, 2001 at 11:43 UTC
To clarify what the problem is: your code assumes that any given day is 24 hours long - as we enter and leave DST that is not true. You may have been missing a day somw time in March as well :) -- <http://www.dave.org.uk> "The first rule of Perl club is you don't talk about Perl club."	[reply]
Re: Two Otober 27, 2002 using timelocal by cfreak (Chaplain) on Oct 15, 2001 at 22:12 UTC
Any day after the last sunday in october causes problems with daylight savings time. I got around it by adding one hour to the last sunday in october. You can find a similar problem in April. (Note: davorg's answer is probably the better one I subtracted the hour to get it to work right because I was doing stuff with the time in between)	[reply]