#include <stdio.h>
#include <stdlib.h>
#include <time.h>

double slow_power(double x, int n)
{
	int i;

	double r = 1.0;

	for (i = 0; i < n; i++)
		r = r * x;
	return (r);
}

double power(double x, int n)
{
	if (n == 0) return 1;
	else if ((n % 2) == 0)
		return power(x*x, n / 2);
	else return x * power(x*x, (n - 1) / 2);
}

int main(void)
{
	double  x, value_slow, value;
	int n;

	x = 2;
	n = 10;

	value_slow = slow_power(x, n);
	value = power(x, n);


	printf("slow_power(%lf,%d) = %lf \n", x, n, value_slow);
	printf("power(%lf, %d) = %lf \n", x, n, value);
}