Re: [Haskell-cafe] Haskell-Cafe Digest, Vol 99, Issue 9

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.miljenovic@gmail.com> wrote:

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Hi This is a very simple basic case, but I have a little trouble with

On 4 November 2011 16:21, yrazes wrote: this... I

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hope somebody can help me

First of all, it would help if you said what your actual trouble is.

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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).

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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.Miljenovic@gmail.com IvanMiljenovic.wordpress.com