1. How can I STOP a cursed recursion?
With some difficulty, I built a recursive procedure, which seems to work
fine, except that I can't get it to STOP.
It knows when it gets to where it should stop, & I put return in at that
point, & when that didn't work, I set an external variable to 1 (=finished)
when it got to that point, and added a test at the beginning of the procedure
to "return" if it saw that var "finished", but that didn't work either.
The procedure was to take a sequence of sequences like what "folder" would
have when adding items to a TreeView, and go thru them to compute the correct
positions to put those items into in a "horizontal" treeView. The procedure
worked thru the items in a correct fashion, got to the last item just below
the root item, knew it was where it should stop, but continues to maybe
"unravel" previous left-over recursions, or something?????
Is there some way to just STOP a procedure, even if it has been working
recursivly?? Or maybe recursion is supposed to be limited to FUNCTIONS?
procedure Help!()
print(1,"help!")
Help{}
-- How can I stop!?
end procedure
Help!
Dan
2. Re: How can I STOP a cursed recursion?
Hi
Is your stop variable local or global - it needs to be global
integer stop_me
function foo()
--do stuff
--result to break out
stop_me = 1
foo()
if stop_me = 1 then
end function
3. Re: How can I STOP a cursed recursion?
I hit return too early, but you get the idea.
Chris
4. Re: How can I STOP a cursed recursion?
Dan Moyer wrote:
>
>
> With some difficulty, I built a recursive procedure, which seems to work
> fine, except that I can't get it to STOP.
>
> It knows when it gets to where it should stop, & I put return in at that
> point, & when that didn't work, I set an external variable to 1 (=finished)
> when it got to that point, and added a test at the beginning of the procedure
> to "return" if it saw that var "finished", but that didn't work either.
>
> The procedure was to take a sequence of sequences like what "folder" would
> have when adding items to a TreeView, and go thru them to compute the correct
> positions to put those items into in a "horizontal" treeView. The procedure
> worked thru the items in a correct fashion, got to the last item just below
> the root item, knew it was where it should stop, but continues to maybe
> "unravel" previous left-over recursions, or something?????
>
> Is there some way to just STOP a procedure, even if it has been working
> recursivly?? Or maybe recursion is supposed to be limited to FUNCTIONS?
>
>
> procedure Help!()
> print(1,"help!")
> Help{}
> -- How can I stop!?
> end procedure
>
> Help!
>
> Dan
Hi Dan,
Try please:
procedure Help()
if get_key()!=-1 then return end if
print(1,"help!")
Help()
-- How can I stop!?
end procedure
Help()
Regards,
Igor Kachan
kinz at peterlink.ru
5. Re: How can I STOP a cursed recursion?
Igor Kachan wrote:
>
> Dan Moyer wrote:
> >
> >
> > With some difficulty, I built a recursive procedure, which seems to work
> > fine, except that I can't get it to STOP.
> >
> > It knows when it gets to where it should stop, & I put return in at that
> > point, & when that didn't work, I set an external variable to 1 (=finished)
> > when it got to that point, and added a test at the beginning of the
> > procedure
> > to "return" if it saw that var "finished", but that didn't work either.
> >
> > The procedure was to take a sequence of sequences like what "folder" would
> > have when adding items to a TreeView, and go thru them to compute the
> > correct
> > positions to put those items into in a "horizontal" treeView. The procedure
> > worked thru the items in a correct fashion, got to the last item just below
> > the root item, knew it was where it should stop, but continues to maybe
> > "unravel" previous left-over recursions, or something?????
> >
> > Is there some way to just STOP a procedure, even if it has been working
> > recursivly?? Or maybe recursion is supposed to be limited to FUNCTIONS?
> >
> >
> > procedure Help!()
> > print(1,"help!")
> > Help{}
> > -- How can I stop!?
> > end procedure
> >
> > Help!
> >
> > Dan
>
>
> Hi Dan,
>
> Try please:
> }}}
<eucode>
> procedure Help()
> if get_key()!=-1 then return end if
> print(1,"help!")
> Help()
> -- How can I stop!?
> end procedure
> Help()
> </eucode>
{{{
>
> Regards,
> Igor Kachan
> kinz at peterlink.ru
Thanks Igor, but I want the *procedure* to stop itself when it sees by test
that it should be finished, not a user action stop it.
eg:
procedure Help()
print(1,"help!")
Help()
if getTime() = 6am then
STOP! -- How can I let the procedure *stop itself*!?
end if
end procedure
Help()
Dan
6. Re: How can I STOP a cursed recursion?
ChrisBurch2 wrote:
>
> Hi
>
> Is your stop variable local or global - it needs to be global
>
> }}}
<eucode>
> integer stop_me
> function foo()
>
> --do stuff
> --result to break out
> stop_me = 1
>
> foo()
> if stop_me = 1 then
>
>
> end function
> </eucode>
{{{
Chris,
I didn't DECLARE the stop variable as GLOBAL,
but I did do it just like you did, with the stop variable outside and
just before the PROCEDURE. I presume you were going
to put a "return" inside the "if stop_me then", which is what I did do,
but that is what isn't working.
Not really knowing what I'm doing, I'm concerned that maybe recursive
PROCEDURES are a no-no, that maybe they have to be FUNCTIONS???
Dan
7. Re: How can I STOP a cursed recursion?
Dan Moyer wrote:
<snip>
> Is there some way to just STOP a procedure, even if it has been working
> recursivly??
Yes, it is.
> Or maybe recursion is supposed to be limited to FUNCTIONS?
No.
> procedure Help!()
> print(1,"help!")
> Help{}
> -- How can I stop!?
> end procedure
>
> Help!
integer Count, NumTimes
procedure Help()
puts(1,"Help!\n")
Count += 1
if Count < NumTimes then
Help()
end if
end procedure
Count = 0
NumTimes = 3
Help()
The code above prints "Help!\n" three times. Often it is nice to use an
additional non-recursive routine, which "wraps" the recursive routine, e.g.:
integer Count, NumTimes
procedure Help()
puts(1,"Help!\n")
Count += 1
if Count < NumTimes then
Help()
end if
end procedure
global procedure Call_Help(integer times)
-- This is the routine which is called by the user.
Count = 0
NumTimes = times -- copy to local variable
Help()
end procedure
Call_Help(3)
Regards,
Juergen
8. Re: How can I STOP a cursed recursion?
Dan Moyer wrote:
>
> Igor Kachan wrote:
> >
> > Dan Moyer wrote:
> > >
> > >
> > > With some difficulty, I built a recursive procedure, which seems to work
> > > fine, except that I can't get it to STOP.
> > >
> > > It knows when it gets to where it should stop, & I put return in at that
> > > point, & when that didn't work, I set an external variable to 1
> > > (=finished)
> > > when it got to that point, and added a test at the beginning of the
> > > procedure
> > > to "return" if it saw that var "finished", but that didn't work either.
> > >
> > > The procedure was to take a sequence of sequences like what "folder" would
> > > have when adding items to a TreeView, and go thru them to compute the
> > > correct
> > > positions to put those items into in a "horizontal" treeView. The
> > > procedure
> > > worked thru the items in a correct fashion, got to the last item just
> > > below
> > > the root item, knew it was where it should stop, but continues to maybe
> > > "unravel" previous left-over recursions, or something?????
> > >
> > > Is there some way to just STOP a procedure, even if it has been working
> > > recursivly?? Or maybe recursion is supposed to be limited to FUNCTIONS?
> > >
> > >
> > > procedure Help!()
> > > print(1,"help!")
> > > Help{}
> > > -- How can I stop!?
> > > end procedure
> > >
> > > Help!
> > >
> > > Dan
> >
> >
> > Hi Dan,
> >
> > Try please:
> > }}}
<eucode>
> > procedure Help()
> > if get_key()!=-1 then return end if
> > print(1,"help!")
> > Help()
> > -- How can I stop!?
> > end procedure
> > Help()
> > </eucode>
{{{
> >
> > Regards,
> > Igor Kachan
> > kinz at peterlink.ru
>
> Thanks Igor, but I want the *procedure* to stop itself when it sees by test
> that it should be finished, not a user action stop it.
>
> eg:
> }}}
<eucode>
> procedure Help()
> print(1,"help!")
> Help()
> if getTime() = 6am then
> STOP! -- How can I let the procedure *stop itself*!?
> end if
>
> end procedure
> Help()
> </eucode>
{{{
>
> Dan
Hi Dan.
In any case, to stop a recursive procedure you must test its ending *before*
calling it. If not, it will recurse forever, until it eats all available
storage.
Typical example (code not tested)
function factorial (atom x)
if x = 0 then
return 1
end if
return factorial(x - 1) * x
end function
9. Re: How can I STOP a cursed recursion?
Juergen Luethje wrote:
>
> Dan Moyer wrote:
>
> <snip>
>
> > Is there some way to just STOP a procedure, even if it has been working
> > recursivly??
>
> Yes, it is.
>
> > Or maybe recursion is supposed to be limited to FUNCTIONS?
>
> No.
>
> > procedure Help!()
> > print(1,"help!")
> > Help{}
> > -- How can I stop!?
> > end procedure
> >
> > Help!
>
> }}}
<eucode>
> integer Count, NumTimes
>
> procedure Help()
> puts(1,"Help!\n")
> Count += 1
> if Count < NumTimes then
> Help()
> end if
> end procedure
>
> Count = 0
> NumTimes = 3
> Help()
> </eucode>
{{{
>
> The code above prints "Help!\n" three times. Often it is nice to use an
> additional non-recursive routine, which "wraps" the recursive routine, e.g.:
>
> }}}
<eucode>
> integer Count, NumTimes
>
> procedure Help()
> puts(1,"Help!\n")
> Count += 1
> if Count < NumTimes then
> Help()
> end if
> end procedure
>
> global procedure Call_Help(integer times)
> -- This is the routine which is called by the user.
> Count = 0
> NumTimes = times -- copy to local variable
> Help()
> end procedure
>
> Call_Help(3)
> </eucode>
{{{
>
> Regards,
> Juergen
Juergen,
Ok, that looks somewhat promising. What I think you're saying is instead
of trying to STOP the recursion, only ask that it be done again from within
itself if some condition is met, ie, if it's not *finished* doing something.
I'll give that a try after I get some sleep.
Thanks!
Dan
10. Re: How can I STOP a cursed recursion?
Ricardo M. Forno wrote:
>
> Hi Dan.
> In any case, to stop a recursive procedure you must test its ending *before*
> calling it. If not, it will recurse forever, until it eats all available
> storage.
> Typical example (code not tested)
>
> function factorial (atom x)
> if x = 0 then
> return 1
> end if
> return factorial(x - 1) * x
> end function
Hi Ricardo,
Here's like what I did, except that I have a number of other tests inside
the procedure which can re-call the procedue with different values to
act on, (those tests & consequences DID work), but the STOPPING didn't work:
integer STOP
STOP = 0
procedure Help()
if STOP then
return
end if
print(1,"help!")
Help()
if getTime() = 6am then
STOP = 1 -- How can I let the procedure *stop itself*!?
end if
end procedure
Help()
After I get some sleep,
I'll try Juergen's suggestion, which I think is to only call the procedure
from within itself when some "*not*-finished" condition is met, rather than
trying to use "return" to STOP it when the finished condition *is* met.
Thanks,
Dan
11. Re: How can I STOP a cursed recursion?
Dan Moyer wrote:
>
> Ricardo M. Forno wrote:
> >
> > Hi Dan.
> > In any case, to stop a recursive procedure you must test its ending *before*
> > calling it. If not, it will recurse forever, until it eats all available
> > storage.
> > Typical example (code not tested)
> >
> > function factorial (atom x)
> > if x = 0 then
> > return 1
> > end if
> > return factorial(x - 1) * x
> > end function
>
> Hi Ricardo,
>
> Here's like what I did, except that I have a number of other tests inside
> the procedure which can re-call the procedue with different values to
> act on, (those tests & consequences DID work), but the STOPPING didn't work:
>
> integer STOP
> STOP = 0
> procedure Help()
> if STOP then
> return
> end if
> print(1,"help!")
> Help()
> if getTime() = 6am then
> STOP = 1 -- How can I let the procedure *stop itself*!?
> end if
>
> end procedure
> Help()
>
> After I get some sleep,
> I'll try Juergen's suggestion, which I think is to only call the procedure
> from within itself when some "*not*-finished" condition is met, rather than
> trying to use "return" to STOP it when the finished condition *is* met.
>
> Thanks,
> Dan
Ricardo,
I see I should have paid more attention to what you said, because if my code
really did what my example did, then the set STOP is never encountered.
I'll have to look at my actual code closer in relation to what you said.
Thanks,
Dan
12. Re: How can I STOP a cursed recursion?
Dan Moyer wrote:
>
> Igor Kachan wrote:
> >
> > Dan Moyer wrote:
> > >
> > >
> > > With some difficulty, I built a recursive procedure, which seems to work
> > > fine, except that I can't get it to STOP.
> > >
> > > It knows when it gets to where it should stop, & I put return in at that
> > > point, & when that didn't work, I set an external variable to 1
> > > (=finished)
> > > when it got to that point, and added a test at the beginning of the
> > > procedure
> > > to "return" if it saw that var "finished", but that didn't work either.
> > >
> > > The procedure was to take a sequence of sequences like what "folder" would
> > > have when adding items to a TreeView, and go thru them to compute the
> > > correct
> > > positions to put those items into in a "horizontal" treeView. The
> > > procedure
> > > worked thru the items in a correct fashion, got to the last item just
> > > below
> > > the root item, knew it was where it should stop, but continues to maybe
> > > "unravel" previous left-over recursions, or something?????
> > >
> > > Is there some way to just STOP a procedure, even if it has been working
> > > recursivly?? Or maybe recursion is supposed to be limited to FUNCTIONS?
> > >
> > >
> > > procedure Help!()
> > > print(1,"help!")
> > > Help{}
> > > -- How can I stop!?
> > > end procedure
> > >
> > > Help!
> > >
> > > Dan
> >
> >
> > Hi Dan,
> >
> > Try please:
> > }}}
<eucode>
> > procedure Help()
> > if get_key()!=-1 then return end if
> > print(1,"help!")
> > Help()
> > -- How can I stop!?
> > end procedure
> > Help()
> > </eucode>
{{{
> >
> > Regards,
> > Igor Kachan
> > kinz at peterlink.ru
>
> Thanks Igor, but I want the *procedure* to stop itself when it sees by test
> that it should be finished, not a user action stop it.
>
> eg:
> }}}
<eucode>
> procedure Help()
> print(1,"help!")
> Help()
> if getTime() = 6am then
> STOP! -- How can I let the procedure *stop itself*!?
> end if
>
> end procedure
> Help()
> </eucode>
{{{
>
> Dan
Ok, no problem, try please:
integer n n=0
procedure Help()
if n=5 then return end if
puts(1,"help!")
n+=1
Help()
end procedure
Help()
atom T T=time()
procedure Help_()
if time()-T > 20 then return end if
puts(1,"help!")
Help_()
end procedure
Help_()
Regards,
Igor Kachan
kinz at peterlink.ru
13. Re: How can I STOP a cursed recursion?
Hi
Sorry, stuff got a bit garbled.
I tend to use functions, because its easier to break out of a function than
a procedure.
This is the way I do it
Generally you need a global indicator variable. This tells the loop, and all
previous loop iterations to stop.
An infinite loop within the procedure
integer break_free --this is global to the program
break_free = 0
procedure foo()
while 1 do
if break_free = 1 then
exit
end if
--do stuff
--are conditions met to exit loop
if conditions met then
break_free = 1
end if
foo()
end while
end procedure
Note the position of loop testing, and setting the global break free
variable - if you've recursed (?) 10 times, then you exit the loop 10 times
You must also reset break_free to 0 immediately after calling foo() for the
first time
Chris
14. Re: How can I STOP a cursed recursion?
On Mon, 19 Jun 2006 06:33:36 -0700, Dan Moyer
<guest at RapidEuphoria.com> wrote:
>Is there some way to just STOP a procedure, even if it has been working
>recursivly??
find(bed,house)
sleep()
Seriously, I would make a very small test dataset and trace it.
Regards,
Pete
15. Re: How can I STOP a cursed recursion?
Dan Moyer wrote:
> Ricardo M. Forno wrote:
>
>> Hi Dan.
>> In any case, to stop a recursive procedure you must test its ending *before*
>> calling it. If not, it will recurse forever, until it eats all available
>> storage.
>> Typical example (code not tested)
>>
>> function factorial (atom x)
>> if x = 0 then
>> return 1
>> end if
>> return factorial(x - 1) * x
>> end function
>
> Hi Ricardo,
>
> Here's like what I did, except that I have a number of other tests inside
> the procedure which can re-call the procedue with different values to
> act on, (those tests & consequences DID work), but the STOPPING didn't work:
>
> integer STOP
> STOP = 0
> procedure Help()
> if STOP then
> return
> end if
> print(1,"help!")
> Help()
> if getTime() = 6am then
> STOP = 1 -- How can I let the procedure *stop itself*!?
> end if
>
> end procedure
> Help()
>
> After I get some sleep,
> I'll try Juergen's suggestion, which I think is to only call the procedure
> from within itself when some "*not*-finished" condition is met, rather than
> trying to use "return" to STOP it when the finished condition *is* met.
No, that's not the point. Previously I wrote ...
integer Count, NumTimes
procedure Help()
puts(1,"Help!\n")
Count += 1
if Count < NumTimes then
Help()
end if
end procedure
Count = 0
NumTimes = 3
Help()
... but we can use as well:
integer Count, NumTimes
procedure Help()
puts(1,"Help!\n")
Count += 1
if Count >= NumTimes then
return
end if
Help()
end procedure
Count = 0
NumTimes = 3
Help()
Inspired by Ricardo's post, I see now that the same can be done without
any local (or global) variable:
procedure Help(integer times)
if times > 0 then
puts(1,"Help!\n")
Help(times-1)
end if
end procedure
Help(3)
Or ...
procedure Help(integer times)
if times <= 0 then
return
end if
puts(1,"Help!\n")
Help(times-1)
end procedure
Help(3)
Here is an Introduction to Recursion
<http://personal.vsnl.com/erwin/recintro.htm>.
Regards,
Juergen
--
Please excuse my flawed English. My native language is Euphoria.
16. Re: How can I STOP a cursed recursion?
Hi there Dan,
As others have mentioned, all you need to do is have a 'test' within
your procedure to make sure there is a true exit at some point in
the execution...i think this will illustrate:
constant Data={1,2,3,4,5,0}
integer k
k=0
procedure Help()
k+=1
if Data[k]=0 then
?k
return
else
Help()
end if
end procedure
Help()
The main idea is that the procedure checks some aspect of the data
it's working on and makes a decision to either return or call another
Help(). This of course means that that particular aspect of the data
must be changing while in the procedure so that the procedure can
make an intelligent decision on it's own, without outside help.
The following routine would NOT work because it's data never changes:
constant Data={1,2,3,4,5,0}
integer k
k=1
procedure Help()
if Data[k]!=0 then
Help()
else
return
end if
end procedure
Help()
Just a guess, but your routine may want to test to see if
the next piece of data is a sequence or an atom, and take
the appropriate actions.
BTW, it's true that after a number of recurcive calls the code
will 'unravel' by executing a whole bunch of 'return' statements,
or perhaps just 'end procedure' a whole bunch of times,
but only if it's designed right in the first place 
Take care,
Al
And, good luck with your Euphoria programming!
My bumper sticker: "I brake for LED's"
From "Black Knight":
"I can live with losing the good fight,
but i can not live without fighting it".
"Well on second thought, maybe not."
17. Re: How can I STOP a cursed recursion?
ChrisBurch2 wrote:
>
> Hi
>
> Sorry, stuff got a bit garbled.
>
> I tend to use functions, because its easier to break out of a function than
>
> a procedure.
>
> This is the way I do it
>
> Generally you need a global indicator variable. This tells the loop, and all
> previous loop iterations to stop.
>
> An infinite loop within the procedure
>
> }}}
<eucode>
> integer break_free --this is global to the program
> break_free = 0
>
> procedure foo()
>
> while 1 do
> if break_free = 1 then
> exit
> end if
>
> --do stuff
>
> --are conditions met to exit loop
> if conditions met then
> break_free = 1
> end if
>
> foo()
>
> end while
>
>
> end procedure
>
> </eucode>
{{{
>
> Note the position of loop testing, and setting the global break free
> variable - if you've recursed (?) 10 times, then you exit the loop 10 times
>
> You must also reset break_free to 0 immediately after calling foo() for the
> first time
>
> Chris
Chris,
I must have done something like what you said, because I DID GET MY RECURSION
TO STOP, and I did have a while-loop in it that might have been at least
part of the problem.
I left a message here just about the time you wrote the above, to let people
know that with all of your help the problem was solved, BUT IT DIDN'T GET
POSTED.
And about 15 minutes or so ago I resent a similar message, when I finally
saw that the earlier one never made it here, and THAT ONE never has shown up
either.
I'm hoping this will show up on the forum so all who replied to my question
will know IT'S SOLVED (as far as I can tell), and that I'm grateful for the
help.
Thanks,
Dan
18. Re: How can I STOP a cursed recursion?
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
19. Re: How can I STOP a cursed recursion?
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 there Don,
A week isnt that long on this list, but if you were gone a month im
sure we all would have missed you.
Calling a function from within itself is called 'recursion' and was
an important part of programming...not sure if it is anymore, but
some things are just neater to do using this kind of programming.
It also means the execution not only depends on the instructions in the
source code but also depends on the data at run time.
I think Rob said one time that Euphoria uses a dynamic stack that
can grow as need arises, so that even with a large number of
recursions deeply nested we wont run out of stack space.
Take care,
Al
And, good luck with your Euphoria programming!
My bumper sticker: "I brake for LED's"
From "Black Knight":
"I can live with losing the good fight,
but i can not live without fighting it".
"Well on second thought, maybe not."
20. Re: How can I STOP a cursed recursion?
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
Don,
Why do you think I called it "cursed" recursion, heh heh!
But in fact some things can be done "more elegently" by recursion
(or with much fewer lines of code), and I think some things may be nearly
impossible (?) to do without recursion. I definatly wouldn't have used it
if I had thought I could use some other method instead!!
Here is an Introduction to Recursion that Juergen provided:
<http://personal.vsnl.com/erwin/recintro.htm>.
btw, people were kind enough to not even mention my error in my example,
& some just corrected it.
should be:
procedure Help()
Help() -- since help() would be another procedure entirely
end procedure
and of course, THIS example would just run forever or until it crashed the
system or something, which was in fact my original problem, making it STOP!
Take care,
Dan
21. Re: How can I STOP a cursed recursion?
Dan Moyer wrote:
> Here is an Introduction to Recursion that Juergen provided:
> <http://personal.vsnl.com/erwin/recintro.htm>.\
Good stuff there, but the definition of recursion is a bit long.
I prefer the following:
Recursion - see recursion.
--
Craig
22. Re: How can I STOP a cursed recursion?
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.
