RE: [Dev-C++] recursion

[Ioannis V. <no...@ho...>]

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From: Per Westermark=0D
Date: =D0=E1=F1=E1=F3=EA=E5=F5=DE, 14 =D6=E5=E2=F1=EF=F5=DC=F1=E9=EF=F2 2=
003 2:38:47 =EC=EC=0D
To: Jaap de Wolff=0D
Cc: dev...@li...=0D
Subject: RE: [Dev-C++] recursion=0D
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I think you got a bit confused about terminology.=0D
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Looping and iteration is actually the same thing.=0D
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=3D=3D> Yes you are right.=0D
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However, recursion is not anything that should be specifically avoided.=0D
It's a question of what problem to solve.=0D
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The trivial example of the faculty function seems to be the most quoted=0D
example for the use of a loop instead of recursion, but the example is=0D
quite bad, since it's faculty is easier to implement and runds faster as =
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loop.=0D
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There are matematical rules that makes it possible to rewrite any=0D
iterative function into a recursive function. And in the same way, any=0D
recursive function may be converted to use state queues to store the=0D
recursive state.=0D
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Use recursion when recursion results in faster run-time, or an easier=0D
implementation. In other cases, select an iterative approach.=0D
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=3D=3D> Recursion resulting to faster run-time is something close to the
impossible. I agree with the "easier implementation" + "while it does not
introduce significant run-time and space costs".=0D
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Examples where recursion faster and/or easier:=0D
- light-tree evaluation in a ray tracer.=0D
- parsing of mathematical expressions=0D
- some recursively defined functions, such as Ackerman=0D
- regular expression pattern matching=0D
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=3D=3D> The "faster" thing is tough to prove. I agree with the "easier".=0D
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Ioannis Vranos=0D
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* Programming pages: http://www.noicys.freeurl.com=0D
* Alternative URL: http://run.to/noicys=20