tTransformer

Transformer.hs

module Transformer (dec2bin, bin2dec, dec2hex, hex2dec, num2letters, letters2num) where

dec2bin :: Int -> [Int]
dec2bin n
    |n==0 = []
    |otherwise = (dec2bin (div n 2))++[mod n 2]

bin2dec :: [Int] -> Int
bin2dec bs = foldl1 (\x y ->x*2+y) bs

dec2hex :: Int -> String
dec2hex n
    |n==0 = ""
    |otherwise = (dec2hex (div n 16))++(num2letters (mod n 16))

hex2dec :: String -> Int
hex2dec bs = foldl1 (\x y ->x*16+y) (map letters2num bs)

num2letters :: Int -> String
num2letters x
    |x == 10 = "a"
    |x == 11 = "b"
    |x == 12 = "c"
    |x == 13 = "d"
    |x == 14 = "e"
    |x == 15 = "f"
    |x >= 16 = "error"
    |otherwise = show x

letters2num :: Char -> Int
letters2num x
    |x == '0' = 00
    |x == '1' = 01
    |x == '2' = 02
    |x == '3' = 03
    |x == '4' = 04
    |x == '5' = 05
    |x == '6' = 06
    |x == '7' = 07
    |x == '8' = 08
    |x == '9' = 09
    |x == 'a' = 10
    |x == 'b' = 11
    |x == 'c' = 12
    |x == 'd' = 13
    |x == 'e' = 14
    |x == 'f' = 15
    |otherwise = 0

tTransformer.hs

import TAP
import Transformer

main = runTests $ do
    planTests 4

    is (dec2bin 10) [1,0,1,0] $ Just "decimal to binary conversion"
    is (bin2dec [1,0,1,0]) 10 $ Just "binary to decimal conversion"
    is (dec2hex 1234) "4d2" $ Just "decimal to hexadecimal conversion"
    is (hex2dec "4d2") 1234 $ Just "hexadecimal to decimal conversion"