I want my function to read in an integer and return the square root rounded down to the nearest integer. This is what I've tried:
roundSqrt :: Int -> Int
roundSqrt x = floor (sqrt x)
The error I get is, "Could not deduce (Floating a) arising from a use of -sqrt'", but I don't understand what this means.
The type of sqrt is:
λ> :t sqrt
sqrt :: Floating a => a -> a
The type of floor is:
λ> ::t floor
floor :: (RealFrac a, Integral b) => a -> b
So, sqrt needs a type which has a Floating constraint. You can use the fromIntegral function to achieve that:
roundSqrt :: Int -> Int
roundSqrt x = floor (sqrt (fromIntegral x))