-divides a b = (mod a b == 0) +divides a b = (mod b a == 0) On Dec 20, 2005, at 11:09 AM, Daniel Carrera wrote:
John Peterson wrote:
Add a type signature: prime :: Integer -> Bool It's defaulting to Int and you're getting overflows
Thanks. Hmm... it's still not working.
Btw, I mis-reported the problem. The offending number is 38466629, which is /not/ prime but the sample program reports as prime.
38466629 = 31 * 1240859
The offending program is: --//-- prime :: Integer -> Bool prime n = not (factors 2 n)
factors :: Integer -> Integer -> Bool factors m n | m == n = False | m < n = divides m n || factors (m+1) n
divides :: Integer -> Integer -> Bool divides a b = (mod a b == 0) --//--
The math behind the program seems correct... :(
Cheers, Daniel.
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