public class Solution { public double Power(double base, int exponent) { if(exponent > 0) return func(base,exponent); if(exponent < 0) return 1.0 / func(base,0-exponent); else return 1.0; } private double func(double base, int exponent) { if(exponent == 1) return base; return base * Power(base, --exponent); } }