Thank you so much Ivan!!! main :: IO ( ) main = let a = 8 b = 3 c = 15 in print(b / a * c)
This code works!!! :) Julita On Fri, Nov 4, 2011 at 12:53 AM, Ivan Lazar Miljenovic < ivan.miljeno...@gmail.com> wrote: > On 4 November 2011 16:21, yrazes <yra...@gmail.com> wrote: > > Hi > > This is a very simple basic case, but I have a little trouble with > this... I > > hope somebody can help me > > First of all, it would help if you said what your actual trouble is. > > > main :: IO() > > main = return :: f > > The "return :: f" bit here doesn't make any sense: > > * :: is used in type signatures, not as an operator in code; you > shouldn't need it (assuming your definition of f below is meant to be > there). > > > tipos :: Int -> Int -> Int -> Float > > tipos a b c > > f = b / a * c > > where > > (a,b,c) = (8,3,15) > > Your definition of tipos isn't complete... what you've actually > defined is a new top-level value `f' (which is of type Fractional a => > a). You need to actually have "tipos a b c" _equal_ something. > > Now, if you want to calculate "b/a*c" for inputs a, b and c, try > something like this: > > import System.Environment(getArgs) > > main :: IO () > main = do [a,b,c] <- getArgs > print $ tipos (read a) (read b) (read c) > > tipos :: Int -> Int -> Int -> Double > tipos a b c = fromIntegral b / fromIntegral b * fromIntegral c > > -- > Ivan Lazar Miljenovic > ivan.miljeno...@gmail.com > IvanMiljenovic.wordpress.com >
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