FUNCTION Factorial (N : IN Positive) RETURN Positive IS
  
-- Computes the factorial of N (N!) recursively
-- Pre : N is defined
-- Post: returns N!
  
BEGIN  -- Factorial   

  IF N = 1 THEN
    RETURN 1;                   -- stopping case   
  ELSE
    RETURN N * Factorial(N-1);  -- recursion   
  END IF;

END Factorial;