recursive leads to stack overflow

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hyena - 24 May 2005 10:05 GMT

I have a recursive function to buid up a tree. When the tree grwos too big,
my java give me a error of stack overflow. si there some solutions rather
then reconsidering the algorithms?

Thanks!

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Thomas Weidenfeller - 24 May 2005 12:17 GMT

> I have a recursive function to buid up a tree. When the tree grwos too big,
> my java give me a error of stack overflow.

Use a better algorithm.

> si there some solutions rather
> then reconsidering the algorithms?

If you really want to waste more memory, read the fine manual:

http://java.sun.com/j2se/1.5.0/docs/tooldocs/windows/java.html#nonstandard

/Thomas

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hyena - 24 May 2005 15:14 GMT

Thanks!

Seems I have to take a careful look at my iterating alogrithm then.:(

> > I have a recursive function to buid up a tree. When the tree grwos too big,
> > my java give me a error of stack overflow.
[quoted text clipped - 9 lines]
>
> /Thomas

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mkrause - 24 May 2005 16:50 GMT

Sigh... *really* helpful Mr Weidenfeller.

If you are getting a stack overflow error, this is NOT because you are
running out of memory. It is because your recursive algorithm does not
properly end its recursion. I would check your logic to see how you
determine when you are done. Typically the pseudocode will be
something like:

Recursive_function(Object current node)
{
// Do pre-recursive stuff here

If (current node is not a leaf node)
{
Recursive_function(current node);
}

// Do post-recursive stuff here
}

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mitch - 24 May 2005 19:40 GMT

To overflow the stack you probably have a LOT of recursive calls to
your method. Don't think tens, think thousands or more.

A typical reason, other than a simple programming logic error, is a
data circularity. Suppose you are trying to display a tree of data
elements, where A refers to B and B refers to C and C refers to A.
Each time an element makes a reference you are going one level deeper
in the tree. Guess what? Your program will be drawing a tree that
looks like

A
B
C
A
B

etc. If your tree algorithm is data dependent you have to be careful
to check for circularities in the data, otherwise you'll end up with
an infinite recursion and a stack overflow.

Hope that helps,

- Mitch Gart

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recursive leads to stack overflow

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