On Mar 25, 2008, at 09:13, Thomas Engel wrote:
My problem is: How can I get the input values into the calculations and back the result to the output.
In an other language I would use global variables for this. So what should I use in haskell?
(I think I know enough haskell to answer this, but I may be telling you all the wrong things.) You'll have to pass the values through, though this can be hidden to some extent. Try changing your functions to have types type Input = (Float, Float, ...) type Output = (Float, Float, ...) inputvalues :: IO Input -- add a "return (ve,de,...)" to the end compute :: Input -> Output outputvalues :: Output -> IO () You could then wrap them in main :: IO () main = do input <- inputvalues outputvalues (compute input) This should do what you want. It might be improved upon by using data types with appropriately named fields instead of tuples so as to keep your variable names around. Cheers Robert