CLD-R Exam 1, Question 22

[kevin57]

I am sitting the LabVIEW CLD-R exam in a few days & attempting some of the sample questions.

Question 22 has me stumped, I just don't get it.

I tried it in LV 2015, and can't seem to get the correct answer.

Can anyone explain to me whats happening here, (I generally don't use recursion, which is why I don't get it I suppose).

I will attach my attempt (that does not work..)

Thanks in advance for anyone's help

[kevin57]

Just to help... attached is the actual question, just in case people don't have the exam papers.

And apparently, this is is the correct answer, (the VI attached)

Thanks

Kevin

[JensG69 · Accepted solution]

Your VI-upload contains one error in comparison to the sample exam. You missed to connect the string "ExprOut". Add this to your VI:

There's also a second smaller problem with the suggested solutions from that sample exam: it is written for an environment with a dot as the decimal point. So it you use a comma as the decimal point, that's why I added explicitly the false constant to the conversion to string.

Regards, Jens

[kevin57]

Very good... thank you very much.

I cannot believe I missed that... no excuse I know, but it was late at night I was trying these (so obvious now that I see it...).

Now that I see it working I get it, thanks heaps.

Kevin

[pcortes2]

Hi you guys.

Still I can´t get why answer D is the right one. Probably something related to recursive function? I was learning about this but still can´t get the reason why D is right.

Can anyone help me?

[JÞB]

Recursion is a bit of a pain to understand. but you Have to have a way to STOP recusing or, you are gonna curse forever. So, example D chooses if it is appropriate to call itself again where C does not.

[pcortes2]

Thanks Jeff, but, opción B also stops recursing the VI. so whats is different there?

[crossrulz]

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@pcortes2 wrote:

Thanks Jeff, but, opción B also stops recursing the VI. so whats is different there?

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The only real difference I am seeing is the Result double being stored in a shift register.  I would need to spend a lot more time going through the code to figure out if it really should be there or not (my current thought is NO).

[JÞB]

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@crossrulz wrote:

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@pcortes2 wrote:

Thanks Jeff, but, opción B also stops recursing the VI. so whats is different there?

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The only real difference I am seeing is the Result double being stored in a shift register.  I would need to spend a lot more time going through the code to figure out if it really should be there or not (my current thought is NO).

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You are thinking correct.  The result of the incurred step is the output of the case.  so the loop output is not what you want as the result.

[pcortes2]

Thanks !!!