Re: LOGO-L> Inverting Numbers

[Yehuda Katz <yehuka@beitberl.beitberl.ac.il>]

Olga Tuzova wrote:
> 
> Hello everybody,
> 
> I'd like to introduce you to some rather interesting examples
> proposed by teachers S.Gorlitskaya and I.Kuznetsova from
> St.Petersburg and posted in Russian newspaper "Informatics".
> I think these examples are in time for our "word games".
> 
> Here are  the first ones.
> 
> The main procedure reads a number as a word.
> how_digits? counts the "sensible" digits of the number.
> Then invert calls inverty, which returns the  inverted number.
> 
> I've slightly changed the initial code, and if there is something
> wrong here, it's my fault.
> ---------------------------------
> to how_digits? :n
> ;counts the "sensible"(?) digits of the number
> if emptyp :n [op 0]
> ifelse not (first :n)=0[op count :n]~
>                        [op how_digits? butfirst :n]
> end
> 
> to invert :n
> op inverty how_digits? :n :n 0
> end
> 
> to inverty :k :n :new_n
> ; inverts the initial number :n and returnes it as :new_n
> if :k=0 [op :new_n]
> op inverty :k-1 int :n/10 10*:new_n+remainder :n 10
> end
> 
> to main
> pr [input any number, it may begin with 0  ==>]
> pr  invert rw
> end
> ------------------------------------------------------


Hello Olga,

You can reverse ANY word, not only numbers, by the following function:

=================================
to reverse :wrd
if 2>count :wrd[op :wrd]
op word last :wrd reverse bl :wrd
end
=================================

Try it by PR REVERSE 1997 or PR REVERSE "H2SO4

Regards...

[[Yehuda]]

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