Achim Schneider wrote:

Anonymous Anonymous wrote:

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fromIntToString :: Int -> String

intOfString = sum . map (uncurry (*)) . zip (map (10^) [0..]) . map intOfChar . reverse

/me hides under a stone and tries again, this time with the correct problem: import Data.List charOfInt :: Int -> Char charOfInt c | c >= 0 && c <= 9 = toEnum (c + fromEnum '0') charOfInt _ = undefined stringOfInt :: Int -> String stringOfInt = let f (-1) = Nothing f n = let (r,c) = n `divMod` 10 in Just $ if r == 0 then (c, (-1)) else (c, r) in map charOfInt . reverse . unfoldr f That -1 thing is clearly inelegant, but I don't feel like struggling with off-by-one errors, right now. Negative numbers are left as an exercise. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited.

Thank you all for your answers, you've all been a great help to me!

Hello, an answer from me, this is NOT the homework assignment. For my own homework assignment, I had to create custom data types and convert a string containing my datatype into my datatype. I will not expose my datatype, but it is something with logical operators. My approach would be using "operator recognition", I've written a function that can search those "operators". However I was wondering how they would do it with intergers because intergers are in a infinity set! But I couldn't figure it out =(. Thanks for answering you all! 2009/3/22 John Dorsey

Anonymous One,

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I'm new to haskell, I'm wondering how can you write a function that will do the following: fromIntToString :: Int -> String

Is this a homework assignment, perchance? Please take a look at http://www.haskell.org/haskellwiki/Homework_help Everyone here is glad to help, but we're also sensitive on academic honesty.

With that said, you've done the first step, which is writing down the function's type. You don't want to iterate over all possible Int values, so maybe a recursive definition is in order. What are the cases to consider? Like, what happens if you have a negative number...

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this is a cast function to cast an Int to a String. I know such function

By the way, "cast" is probably the wrong word for what you want. You're building a string representation of an Integer; in my view it's not "just" a type conversion.

Good luck, John

Rafael Cunha de Almeida wrote:

This e-mail is offtopic, but I suppose being a little offtopic every now and then isn't that bad, specially if the subject is interesting. So, here I go.

It's the cafe'. Very little is strictly off-topic here, and certainly not this. I'm happy to help anyone who's trying to learn, but I will not willingly subvert anyone's classroom rules, as a matter of academic honesty. I think that matters at any level of school. I accept that it can't be enforced perfectly, or anywhere near so. I didn't mean to accuse the original poster, and I trust I didn't come accross that way. I don't think it's a bad idea to point out that an anonymous question like this one may look suspicious, or that many instructors follow this forum. None of that should give offense. But I also provided some hints. I think a good and fun way to help with problems like that is to iteratively guide someone to their answer, instead of giving it to them straight-up. Just to be clear, I also have no criticism of the other replies. Anyone giving voluntary help should and will apply their own rules.

The only reason people would want the answer of an assignment instead of actually doing it themselves is if they don't care about actually doing it. That is, they don't want to learn haskell, they just want to pass a class. In that case, do we really want to _make_ them learn?

In that case I have no interest in forcing them to learn or in helping them get a grade. But I'm always optimistic that someone's willing to learn. I've been proven wrong, but not often. Cheers, John