On 23 Mar 2009, at 2:20 am, Anonymous Anonymous wrote:
Hello,
I'm new to haskell, I'm wondering how can you write a function that will do the following:
fromIntToString :: Int -> String
this is a cast function to cast an Int to a String.
It cannot be. What could it possibly mean to "cast" an Int to anything, let alone a string? Haskell isn't C. (Nor is it PL/I.) What to do depends on what you _want_ to do. For example, fromIntToString n = replicate n 'I' will convert 1 to "I", 2 to "II", 3 to "III", and so on. Assuming that you mean that you want a decimal representation of the integer, Read The Fine Manual to find out what 'show' will do. This may well be a homework question, in which case consider: you want to construct an element of a recursively defined data type (list of character). do you *have* a recursively defined data type to start from? If you first distinguish between negative and non-negative integers, do you have a recursively defined data type then? How could you use `div` and `mod` to treat non-negative integers _as if_ they formed a recursively defined data type? What would the base case be? What would the step case be?