prog4

package laboration1;

public class Prog4 {

	public static void main(String[] args){

		double x;
		int n;
		x = Double.parseDouble(args[0]);
		n = Integer.parseInt(args[1]);
		System.out.println("x= "+ x + " and k = "+ n +", x^k= "+ rec_raise(x,n));
		System.out.println("x= "+ x + " and k = "+ n +", x^k= "+ rec_raise_eff(x,n));
	}

	public static double rec_raise(double x, int n){

		if(n == 0){
			return 1.0;
		}else{
			return (x * rec_raise(x,n-1));
		}
	}

	public static double rec_raise_eff(double x, int n){

		double temp;

		if (n == 0){
			return 1.0;
		}
		if (n%2 == 0){
			temp = rec_raise_eff(x,n/2);
			return  temp * temp;
		}else{
			temp = rec_raise_eff(x,(n-1)/2);
			return x * temp * temp;
		}
	}
}