it sounds like you will have your information loaded every once in a while
from a PC
why not have your pc upload a sorted list then binary search the mmc.

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Kresho
Sent: Thursday, April 22, 2004 10:58 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC:] Sorting through millions of numbers


Thanks for all the replies.

> I assume this is for  something comparable to a car wash system -
> you buy a
> "ticket" which is recorded in the system and it is removed once utilised.

Good guess but not quite. What it's for is a snack promotion. People will
receive a card encoded with a number. This number is stored with the
time/date as previously specified. Then the card holder swipes their card on
a vending machine to get their free snack. There will obviously be a limited
time for them to redeem said snack, and that's why the date is required.

> You didn't mentioned "PIC" one single time, but I'd guess that
> that's what you'd like to use, right ? :-)

Yes, or something similar. I'm dabbling with some hitachi H8s at the moment
which might be a better fit for this application.

The b-tree and hashing schemes seem like a possibility. However, I think
Adam's response with his practical analysis is probably fitting here. If the
limited time for redemption is kept short enough I can just go through the
data every now and then and delete expired entries and keep the list lean.

If i come up with another solution i'll keep you posted.

Rgds,

Kresho Sprem

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