Re: Two reade loops: which one preferred ?

GA ==> how more cycles (machine-cycles)? 

I guess that adding an %equal is rather unexpensive.
In case of no records a setll and a reade (TWO I/O operations) costs more 
cycles.

Don't laugh: 
I'm from the generation that were taught to use odd number of digits in packed 
decimals because it is cheaper.
I still do this, because typing a '5' is as easy as typing '4' (and the song 
about teaching old dogs..).

Henrik

> From: "G Armour" <garmour400m@xxxxxxxxx>
> To: "Midrange Systems Technical Discussion"
> <midrange-l@xxxxxxxxxxxx>
> Sent: Friday, November 21, 2003 12:41 PM
> Subject: Re: Two reade loops: which one preferred ?
> 
> 
> | Thank goodness for the voice of reason!  <g>
> |
> | Though I wonder, Henrik, why would this cost a few more cycles?  I can't
> | see logically how one could eat more cycles doing it this way.  But, of
> | course, this is not a paramount consideration.
> |
> | GA
> |
> | --- Henrik Krebs <hkrebs@xxxxxxxxx> wrote:
> | > A reason why style #1 might be preferred is that 'Do forever' is
> | > misinformational unless you have a veeery large file.
> | >
> | > But I actually use style #3:
> | > ----- Style #3 -------------------------------------------
> | >
> | > mykey setll record
> | > dou %eof
> | > mykey reade record
> | > if not %eof
> | > ... process ...
> | > endif
> | > enddo
> | >
> | > because I think it's cleaner.
> | > Why?
> | > 1. First of all: Read can return either a) a record or b) an eof flag,
> | > and we (you) only want 'process' in case 'record'
> | >    You could also inside the loop have coded for both situations (select
> | > or if..else)
> | > 2. It's clean: only a single 'read' to control a 'read-loop'.  Both
> | > style #1 and #2 has two or three different routes through the code: zero
> | > records, a record read and no more records
> | > 3. No 'Do forever' that definately is not 'forever'
> | > 4. Same construction (the fewer the better) for 'read entire file'
> | > (except the missing setll of cause).
> | >
> | > It might mean a few more cykles, but they are cheaper than programmer
> | > time
> | >
> | > Henrik