Difference between revisions of "Talk:99 questions/Solutions/31"

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| otherwise = (n `rem` x) /= 0 && isPrime' (x+1) n
  
| otherwise = (n `rem` x) /= 0 && isPrime' (x+1) n
 
</haskell>
  
</haskell>
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== And something as simple as this one... ==
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isPrime :: Int -> Bool
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isPrime n = all (\x -> n `mod`x /= 0) [2..sqr]
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where sqr = floor (sqrt (fromIntegral n :: Double))
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-- Assuming that a number is not a prime if he is divisible by any number between 2 and his sqrt

Revision as of 11:14, 14 October 2013

Does something as simple but as dump as this should be on the wiki ? 

isPrime :: Int -> Bool
isPrime n | n <= 1 = False
isPrime n = isPrime' 2 n
    where isPrime' x n | x*x > n   = True
                       | otherwise = (n `rem` x) /= 0 && isPrime' (x+1) n

And something as simple as this one...

isPrime :: Int -> Bool isPrime n = all (\x -> n `mod`x /= 0) [2..sqr] where sqr = floor (sqrt (fromIntegral n :: Double))

-- Assuming that a number is not a prime if he is divisible by any number between 2 and his sqrt

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