Sum of Fibonacci numbers

Posted by Rafal on Stack Overflow See other posts from Stack Overflow or by Rafal
Published on 2010-05-05T20:52:18Z Indexed on 2010/05/05 21:08 UTC
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fibonacci

Hi,

I'm rather new to Haskell. The problem is to find the sum of all even Fibonacci numbers not greater than 4 million. I can't use lists.

If I understand correctly, the below solution is wrong, because it uses lists:

my_sum = sum $ filter (even) $ takeWhile (< 4000000) fibs

Where fibs is the list of all Fibonacci numbers.

Somehow, I find it difficult not to think in Haskell in terms of lists. Could anyone guide me to a solution to this problem?

Regards

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