Re: LOGO-L> Re: Clayson

[George Mills <mills@softronix.com>]

Many functions in UCBLogo/MSWLogo (and perhaps other logos)
will take a varying number of arguments. To force a function
to use an alternative number of arguments use ()'s. The
non-paren form of ARCTAN assumes one argument but will
alternatively take the 2 argument form.

to sq :n
op :n * :n
end

to staredge :tangle :slope
rt :tangle
fd :slope
lt 2 * :tangle
fd :slope
rt :tangle
end

to stargon :n :R :notch
local "side
local "height
local "tangle
local "slope
make "side 2 * :R * (sin 180 / :n)
make "height :notch * :R * (cos 180 / :n)
make "tangle (arctan :height  :side / 2)
make "slope sqrt (sq (:side / 2) + sq :height)
pu
fd :R
rt 180 - (90 * (:n - 2) / :n)
pd
repeat :n[(staredge :tangle :slope) rt 360 / :n]
lt 180 - (90 * (:n - 2) / :n)
pu
bk :R
pd
end


OMihich@aol.com wrote:
> 
> Hi,
> Working through Visual Modeling I got stucked in the stargon procedure on page
> 140. The problem is probably with arctan which takes one input.
> Here are the procedures:
> 
> to sq :n
> op :n * :n
> end
> 
> to staredge :tangle :slope
> rt :tangle
> fd :slope
> lt 2 * :tangle
> fd :slope
> rt :tangle
> end
> 
> to stargon :n :R :notch
> local "side
> local "height
> local "tangle
> local "slope
> make "side 2 * :R * (sin 180 / :n)
> make "height :notch * :R * (cos 180 / :n)
> make "tangle arctan :height  :side / 2
> make "slope sqrt (sq (:side / 2) + sq :height)
> pu
> fd :R
> rt 180 - (90 * (:n - 2) / :n)
> pd
> repeat :n[(staredge :tangle :slope) rt 360 / :n]
> lt 180 - (90 * (:n - 2) / :n)
> pu
> bk :R
> pd
> end
> 
> Thank you for your help.
> 
> Orlando
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George Mills
email: mills@softronix.com
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