1.2

gistfile1.hs

-- Probeklausur 1.2

data N = Zero | S (N) deriving (Show) -- natürliche Zahlen
data Z = Z (N,N)      deriving (Show) -- ganze Zahlen

class Rechnen a where
  add :: a -> a -> a

instance Rechnen N where
  add m Zero    = m
  add m (S (n)) = S (add m n)

instance Rechnen Z where
  add (Z (m1, n1)) (Z (m2, n2)) = Z (add m1 m2, add n1 n2)