From: Mattia Peronio <m.peronio@...>
Date: 2003-03-16T10:34:14+09:00
Subject: Re: Recursion



On Fri, 14 Mar 2003 00:44:38 +0900, Joel VanderWerf wrote:
>MikkelFJ wrote:
>>"Daniel Carrera" <dcarrera@math.umd.edu>�wrote in message
>>news:20030313010257.GA3381@math.umd.edu...
>>
>>>You mean, like this? :
>>>
>>># Compute the Greatest Common Divisor.
>>>def gcd(a,b)
>>>return a if b == 0
>>>return gcd(b, a % b)
>>>end
>>>
>>>On Thu, Mar 13, 2003 at 09:57:25AM +0900, Mattia Peronio wrote:
>>>
>>>>Please, I need an example of recursive function with 2 or more
>>>>parameters, i.e. the euclidean formula for maximum common divisor.
>>>>thank you very much,
>>>>Mattia
>>
>>
>>May I suggest that we do not directly solve what appears to be home
>>assignments?
>
>Indeed. And as a punishment for this offense, the offending party
>should
>write out the decimal represenatation of
>
>A(5, 5)
>
>where
>
>A(0, n) = n + 1
>A(m+1, 0) = A(m, 1)
>A(m+1, n+1) = A(m, A(m+1, n))
>
>(Ackermann's function)
>
>Oops. Now I guess I gotta do it, too ;)
>
>
>
>

Forget about that!
Being a novice, I was thinking I not to be able to correctly implement recursion.
I discovered my problem was not this.
At that time the ruby interpreter behaved in a strange mood.
When passed a parameter like this to the function


def hallo(a)
  print a 
end

hallo( x**y*x)


it gave me an error ->     undefined local variable or method `*'
so I had to add a line to have my function working


def hallo(a)
  print a 
end

b= x**y*x
hallo( b)


and all worked correctly. Notice that this problem occurred only at that time.

Thanks for your patience.