RE: READC, dou, and For

I've been basted and roasted for this before, but I like to use an array
to shadow a subfile and avoid using the display file keywords.  There is
a performance benefit to using the display file keywords, but they were
developed when dumb terminals used a 9600 baud line and machines were a
lot weaker. I think (I've never tried it) that reading all the records
in a 9999 record subfile and comparing them to an array gives more than
adequate performance. If you have a 9999 record subfile, you ought to
convert it to page at a time before record number 10,000 shows up.  If
you're using page at a time you have the choice of an arrray or disk I/O
once you leave the current screen. In real world subfiles, 3 or 4
screens max, the performance difference is imperceptible to an end user.


I like using a loop where I compare the subfile to the array because I'm
a closet Michael Jackson supporter.  It also makes the purpose of the
code obvious to idiots like me who refuse to take advantage of the
wonderful functionality provided by the display file keywords. (There,
I've admitted the moral degeneracy of my method and my character.) <g>
OTOH I don't judge people who prefer the other way.  It works too.

> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Booth Martin
> Sent: Tuesday, July 12, 2005 1:22 PM
> To: RPG programming on the AS400 / iSeries
> Subject: READC, dou, and For
>
> An interesting discussion came up the other day.  Leastways,
> it was interesting to me.
>
> To read through a subfile in olden days we could use READC
> and SFLNXTCHG. 
>
> Then it became a lot easier and just as fast to loop, reading
> every subfile record, with a dou loop.
>
> Then along came the FOR loop and I am hearing that we should
> use a FOR loop, from 1 to SFLRECS, where SFLRECS is the size
> of the subfile.
>
> What are the thoughts of those here assembled?
>
> ---------------------------------
> Booth Martin
> http://www.martinvt.com
> ---------------------------------
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