Re: LOGO-L> ToonTalk versus MicroWorlds

[yehuda <yehuka@softhome.net>]

Bill Kerr wrote:

I've imitated Ken's ToonTalk factorial demonstrations using MicroWorlds. I
haven't put in the scales (to compare the numbers) or bird (to fetch the
answer) at this stage but they could be added if desired.

I think MicroWorlds allows for multiple representations of factorial better
than ToonTalk. I'm putting this up as a hypothesis to be debated / refuted.
ToonTalk only permits a visual representation (which also requires
abstraction -- Dusty erasing numbers in the thought bubble) whereas in
MicroWorlds you can show it by either a high powered recursive procedure
(most elegant but difficult for unsophisticated users) or a visual / text
combination, which seems to me to require less abstraction (and so would be
more accessible for more kids).

MicroWorlds solutions:
1) Most elegant but difficult:

to factorial :no
if :no = 1 [op 1]
op (product :no  factorial :no - 1)
end

Hi,

This level of programming is suitable for students (kids or grownups alike) who know already what's a function, and what is a recursive function.

A "simpler" solution might be, to take an iterative approach, instead of a recursive one:

to main
ct
factorial readword 1
end

to factorial :num :total
if :num<2[pr :total stop]
factorial :num-1 :num*:total
end

It's basically your third MW program, I think, stripped off from graphics
and animation, in standard Logo.

Please verify that any version of the program "knows" that 0!=1 (your recursive program above has to be slightly modified for this).

Regards and a happy new year,

Yehuda,

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http://www.geocities.com/CollegePark/lab/2276/
e-mail: yehuka@softhome.net
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