HaskellCourse/cm/mypower.hs

-- Slide 15
e1 x n = case n of
	0 -> 1
	_ -> x * e1 x (n - 1)

e2 x n =
	if n == 0
		then 1
		else if even n
			then e2 (x * x) (div n 2)
			else x * e2 (x * x) (div n 2)