RE: dim lights?

Gerald,

It's because the tests of the if statement are processed left to right and 
checking stops once something is found that would make the entire test false.

If you flip the tests around, you check to see if you're going to go out of 
bounds first which stops the test if you will. The statement InputMAD(pos) 
never executes the number of elements in this case which both keeps you from 
getting the error and also ends the loop since the entire statement is now 
false.

To further clarify, consider if the following:

pos = 53
if (InputMAD(53) <> ';') and
    pos < 52
...do stuff
endif

It's pretty clear that this would fail since you now have an out of bounds 
condition. If you rewrite it like this:

pos=53
if pos < 52 and
   (InputMAD(53) <> ';')
...do stuff
endif

You will not get an out of bounds error since the test pos < 52 is false and 
because you used an and with the other test, it makes the entire statement 
false.

Matt

-----Original Message-----
From: Gerald Magnuson [mailto:gmagnuson@xxxxxxxxxxx]
Sent: Thursday, March 25, 2004 12:08 PM
To: RPG programming on the AS400 / iSeries
Subject: Re: dim lights?


Hans,
Are you saying it makes a difference
if we have the "and" on the top line,
or on the next line?
Could you explain why that is?

Hans Boldt (boldt@xxxxxxxxxx) wrote:
>
> Ted Barry wrote:
> > What is wrong with this statement?:
> >
> > dow       (InputMAD(pos) <> ';') and
> >           pos < 52
> > eval      pos = pos + 1
> > enddo
> >
> > Total dims are 52, so why am I getting an array index error?
> >
>
> Rewrite it as:
>
> --------------------------------------
> dow        pos < 52
>             and (InputMAD(pos) <> ';')
> eval      pos = pos + 1
> enddo
> --------------------------------------
>
> and try again. If the first condition is not true, the second won't be
> evaluated.
>
> Cheers! Hans
>
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>

--
Gerald Magnuson
The Knapheide Manufacturing Company
Quincy Illinois


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