Re: Need for separate Input and Output Areas in Display File

no offense intended here, Joe, but that's an RPG programmer's view.

RPG programmer's are used to var-a being var-a everywhere. Traditional COBOL
programmers are not. If you say to a COBOL programmer "var-a" they say
"which one?".

And the RPG programmers that I've taught COBOL to for interactive work, fall
in love with the separate areas because they don't have to come up with
prefixes and multiple occurence structures and other such crap to keep
screen data separate from data file data. Or to hold on to the field they
output, just to do a compare against the field input by the user.

And you ought to see them beam when we then show them move corresponding!
;-)


===========================================================
R. Bruce Hoffman, Jr.
 -- IBM Certified Specialist - iSeries Administrator
 -- IBM Certified Specialist - RPG IV Developer

"There is a crack in everything,
  that's how the light gets in.
    - Leonard Cohen

----- Original Message -----
From: "Joe Pluta" <joepluta@PlutaBrothers.com>
To: <cobol400-l@midrange.com>
Sent: Tuesday, August 13, 2002 9:35 AM
Subject: RE: Need for separate Input and Output Areas in Display File


> ARGH!  Careful here.  I just got bitten by this particular issue.
>
> > > WORKING-STORAGE SECTION.
> > > 01  HEADER-OUTPUT.
> > >     COPY DDS-HEADER-O   OF PAD0137NW.
> > > 01  HEADER-INPUT.
> > >     COPY DDS-HEADER-I   OF PAD0137NW.
>
> This creates separate spaces in memory for each object.  There is no
chance
> for one to overlay the other.
>
> >        01  DSPFILE-area.
> >            copy dds-m1map-o     of OE314D.
> >            copy dds-m2ctl-o     of OE314D.
> >            copy dds-m2sfl-o     of OE314D.
> >            copy dds-m2key-o     of OE314D.
>
> With THIS technique, however, each record shares the same memory location.
> Changes to dds-m1map-o", for example, are reflected in "dds-m2ctl-o".  If
> you're lazy and don't update your variables prior to each WRITE operation,
> you can get decimal data errors quite easily.
>
> Joe
>
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