rounding - Round IO Double to specified number of digits - Haskell -

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is there way round io double? looking function:

ownround :: io double -> io double

with these unit tests:

ownround 0.51 == 0.5 ownround 0.49 == 0.5 ownround 0.5 == 0.5 ownround 0.7132 == 0.7 ownround 0.39 == 0.4

what asking can't had. test cases you've written function

tensround :: double -> double

but type signature wrote function

ownround :: io double -> io double

if meant write test cases as

ownround (return 0.51) == return 0.5 ownround (return 0.49) == return 0.5

and on, every number wrapped io, these implementations work:

tensround :: double -> double tensround d = frominteger (round (d*10)) / 10  ownround :: io double -> io double ownround = fmap tensround

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