Loop structures

[becktho]

Hi

I was wondering, if there exists a while-loop in LV. Now don't think "what kind of problem has this guy - there is a while-loop" - I know there is, but compared to a textual language it's a do-while-loop (footer controled).

I want to know if a header-controled loop exists or if it may come with a future release of LV.

Thomas

[CharlieRodway]

Hi becktho,

I don't know if there's anything in the pipeline, but until then you could try a conjunction of while/case structures.

See attached VI.

[becktho]

Hi Charlie

I know what you mean and use it like this (still your attempt shall be honoured ;)), but I'd like to get rid of this way.

And the best thing for that was a header-controled while-loop.


Thomas

[CharlieRodway]

Hi becktho,

I have raised this topic when I've been at NI (Newbury) before. They are at least aware of the problem, but I don't know if we'll see anything soon 🙂

[Philip_Courtois]

Hi Thomas,

Please make yourself heard the best way by submitting a Product Suggestion through the "feedback" link on www.ni.com/contact. That way, your suggestion will get directed to the appropriate LabVIEW developer.

Have fun!

[altenbach]

If you just want a while loop where the termination condition is checked before each code iteration, use something like in the attached image. I don't think we need an entirely new loop species. 🙂

Message Edited by altenbach on 05-19-2005 07:54 AM

[altenbach]

Thanks for the peanut! 🙂

Strong opinions either way should probably be spelled out in a reply so we can all learn and improve our thinking. 😉

[becktho]

Hi great wizard

Yes your right - your example works. But I think it was easier if I don't have to draw the case-structure all the time. And also to have your loop available in the palette is not the right way, I think.
In addition - if you have several criteria to stop the loop, maybe it must be enlarged too much (I don't like hiding code).

Just for comparison in a textual language you don't write

do{
if(i < 5){
...
}
}while(i < 5)

Thomas

BTW - gave you a five-star rating. But as you see, the average is just 3 :(.

Message Edited by becktho on 05-19-2005 05:29 PM

[altenbach]

Thanks. My main concern was that I could not come up with a simple graphical programming element design that would do what you want directly. I need to ponder a bit more....

Do you have any ideas how it could look like? How should the outputs be handled if it does not execute al all?
(e.g. similar to a FOR loop with zero iterations, which is allowed and defined).

(If the need really exists, I am sure that the wizards at NI will come up with a stunningly beautiful and intuitive new loop structure that does exactly what you want. :))

[Chaos]

If, in a textual language, a standard while loop was *not* available (only a do-while) then how would it be written?
I would think it would turn out something like this:

if( condition ) {
do {
} while(condition)
}

IE, I guess I agree with the first posters in the group on this one 😃

Message Edited by Chaos on 05-19-2005 11:01 AM