Integer Conversion in Haskell. HELP!! The method that I have to implement is con

Question

Integer Conversion in Haskell. HELP!!

The method that I have to implement is

convert numString b1 b2

such that it returns a string representing the value in numString (represented in base b1). It should return a string with the number represented in base b2.

You may not, of course, use any library functions that do all the work for you.

You may use digitToInt (but it only works on '0'-'9' and 'A'-'F'). Make sure you write "import Data.Char" at the top of your file

We want to make our function work with bases up to 35. The way we will do this is to let A=10, B = 11, ... Z= 35.

['A','B'..'Z'] is the list of characters from A to Z (you can do the same for the digit characters).

elem will test if the first argument is a member of the second, list, argument

Here are the functions I defined to solve this (you only have to have convert fully functional):

convert numString b1 b2 -- of course

valNumString (xs) b1 --to get the value of a string

int2Base n b -- integer to string at base b

num2char n -- get character for numbers in range... a mapping from [0..35] to [ '0'..'9','A'..'Z']

dig2Int dChar -- converts character to integer

indexInto x (y:ys) --gets the index of a value into a list, e.g. indexInto 4 [0..4] = 4

Test Cases:

*Main> convert "123" 10 10

"123"

*Main> convert "123" 8 10

"83"

*Main> convert "F" 16 10

"15"

*Main> convert "FF" 16 10

"255"

*Main> convert "XXX" 35 10

"41613"*

Main> 33*35*35+33*35+33

41613

Explanation / Answer

Prelude> (reads "123 abc") :: [(Integer, String)]
[(123," abc")]
Prelude> show 123
"123"

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