Power. NK where K is a natural number - back to content

	   
	    Example:

	   ?- X is 2 ^ 3. /* Prolog symbol for power is ^ */
	   X = 8
	   ?- power(2,3,R).
	   R = 8
	   ?- power(2,0,R).
	   R = 1


  
       /* our definion of ^ */  
	   power(N,0,1):- !.
	   power(N,K,R):- K1 is K-1,power(N,K1,R1),R is R1*N.