RE: [MLUG - DISCUSSION] 10/01/01

[Jonathan King <EMAIL:PROTECTED>]

On Mon, 1 Oct 2001, Ross, Matt wrote:

> sorry,
> 09/31/1390
>
> -----Original Message-----
> From: Ross, Matt [mailto:EMAIL:PROTECTED]
> Sent: Monday, October 01, 2001 1:09 PM
> To: EMAIL:PROTECTED
> Subject: RE: [MLUG - DISCUSSION] 10/01/01
>
>
> 12/31/1321

OK, so here's the perl program that spits back all of the years that have
what I'll call a "palindate"; obviously, there can only be one such day
per year. :-)  There are just 372 of these.

#!/usr/bin/perl -lw

foreach my $year (1..9999){    # no palindates for 5 digit years; no year 0
    $_=sprintf("%04d",$year);
    /^                      # we match by digit pairs, starting with:
	(
	 ([0-1][123])       # 1) stuff that reverses to day of the month:
	 |                  #    can't have 00 or anything reversing to
	 ([1-9][0-2])       #    over 31
	 )
	                    # 2) stuff that reverses to the month means:
         ([1-9]0            #    a) something must be there (no 00)
         |
          [0-2]1)           #    b) if not months 01-09, has to reverse to
                            #       10,11,12

      $/x                   # 3) make sure we match only 4 digits, and
                            #    /x means I can comment this regexp

     && print;
}

# jking



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