剑指offer-6：竖着整数次方

public class Solution {
    public double Power(double base, int exponent) {
        double result = 1;
        if(exponent==0){
            return 1;
        }
        if(exponent==1){
            return base;
        }
        if(exponent>1){
           for(int i=0;i<exponent;i++){
             result *= base;
            } 
        }
        if(exponent<0){
            base = 1/base;
            for(int i=0;i<-exponent;i++){
             result *= base;
            } 
        }
        return result;
  }
}