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Re: writing recursive functions [message #15649 is a reply to message #15645]

Wed, 02 June 1999 00:00

davidf
Messages: 2866
Registered: September 1996

Senior Member

Martin Downing (m.downing@abdn.ac.uk) writes:

> My aim is to write a function that (recursively) call itself, that can be
> compiled on the fly as with standard code.
> So - whats the problem, well if you _could_ write a function for factorials
> using recursion as:
>
> ------------------------------------------------------------
> ; fact.pro : take 1
> ; example of recursion (I know there's a factorial function!!)
> function fact , n=n
> res = float(n)
> if res gt 1 then $
> res = res * fact(n=res-1)
> return, res
> end
> ; (I used a keyword as otherwise it compiles thinking fact() is a variable)
> ------------------------------------------------------------
>
> ...This will not compile

How about this, using Forward_Function to indicate
that FACT is a function and not a variable. You could
go back to using n as a positional parameter. :-)

function fact , n=n
forward_function fact
res = float(n)
if res gt 1 then $
res = res * fact(n=res-1)
return, res
end

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
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[Message index]

		writing recursive functions By: Martin Downing on Thu, 03 June 1999 00:00
		Re: writing recursive functions By: William Daffer on Wed, 02 June 1999 00:00
		Re: writing recursive functions By: davidf on Wed, 02 June 1999 00:00

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