OpenEuphoria

Re: How can I STOP a cursed recursion?

• Posted by Ricardo M. Forno <rmforno at tutopia.com> Jun 22, 2006
• 604 views

don cole wrote:
> 
> Hello everybody,
> 
> My computer has been broken for about a week. I guess nobody missed me.
> I've been catching up on my Euforum reading. I've seen a lot of talk about
> the code,
> 
> procedure Help()
>   help()
> end procedure
> 
> If this code is not illegal it should be. How can you call a procedure from
> within this procedure? I find this code very disturbing as it goes against all
> the rules. One should be able to call help() from any number of places besides
> help it self. And lastly I don't see any point of doing that way.
> 
> Don Cole

Hi, Don.
Recursion is not only an elegant form of programming some tasks, but
sometimes it is badly needed. It can be shown that what you do by means of
recursion can be done in another way, but sometimes things may become
very difficult in this "other way".
The typical example is (code not tested):
(a should be an integer, but the result may be too large to fit into an
 integer)

function factorial(atom a)
   if a = 0 then
      return 1
   end if
   return a * factorial(a - 1)
end function

This can be done without recursion:

function factorial(atom a)
   atom r
   r = 1
   for i = 2 to a do
      r = r * i
   end for
   return r
end function

This is a bit longer than the recursive version, but this does not show
the real benefits of recursion.
You will find more useful examples of recursion in my General Functions
contributed program, or in my recently updated General Sudoku program.
In this last program, it will be difficult to process an undefined
number of dimensions without using recursion.
Regards.