Rule to calculate power of a number when the exponent is Negative in Prolog?

Question

I have a power function pow that attempts to calculate the value of B to the power of E. So far I handle the cases-
1. exponent i

Answer 1

Don't forget that a^(2b) = (a^b)^2 and x^2 = x*x. It is ok to call a tail-recursive working predicate with accumulator, in a non-tail fashion, from a top-level "UI" predicate. That way you don't have to implement working predicate for negative powers but rather reuse the one for positive power, and alter its result in the top-level predicate (I see this has already been suggested):

pow(B, E, R):- E<0 -> ... ; E=:=0 -> ... ; E>0 -> ... .