[Haskell-cafe] quiry

[Pixel]

"ashutosh dimri" <adimri.iitkgp at gmail.com> writes:

> how to convert a hexadecimal into base 10 integer using haskell . I have
> written a code but its not working for large values , please help

from http://pleac.sourceforge.net/pleac_haskell/numbers.html#AEN118 :


-- "read" handles both octal and hexadecimal when prefixed with 0x or 0o
-- here are versions adding the prefix and calling "read"
hex s = read ("0x" ++ s) :: Integer
oct s = read ("0o" ++ s) :: Integer

-- hex "45" == 69
-- oct "45" == 37
-- hex "45foo" => Exception: Prelude.read: no parse

-- calling explicitly readHex or readOct:
hex = fst . head . Numeric.readHex
oct = fst . head . Numeric.readOct