// converts an integer from base 10 to a string of base x (where 0 > x >= 20)
convertFromDecimal :: Int -> Int -> String -> String convertFromDecimal num toBase accum | toBase < 0 = error "base must be greater than zero" | toBase > 20 = error "base must be <= 20" | num < 0 = error "number cannot be negative" | num == 0 = accum :: String | num > 0 = let chars = "0123456789ABCDEFGHIJ" over = num `mod` toBase remain = num `div` toBase accum' = (chars !! over) : accum in convertFromDecimal remain toBase accum'
