剑指offer_面试题11 数值的整数次方_考察代码的完整性

 

 

测试通过代码：

package t0825;

public class Power {
     public static void main(String[] args){
        System.out.println(Power(2.5,3));
        System.out.println(Power(0.00000001,3));
        System.out.println(Power(0.00000001,-3));
        System.out.println(Power(2,-3));
        System.out.println(Power(10,10));         
     }
     /*
      * 大数问题
      */
     public static double Power(double base, int exponent) {
         double result=1.0;
         if(equal(base,0.0) && exponent<0){ //当基于为零时，多少次方都为零
            return 0.0; 
         }    
         int absExponent=0;
         if(exponent<0)
             absExponent=-exponent;   //如果为负数，取反求倒数；
         else
             absExponent=exponent;
         result = PowerAlthmn(base,absExponent);
         if(exponent<0)
             result = 1.0/result;         
         return result;
     }
     public static boolean equal(double num1,double num2){
        if((num1-num2)>-0.0000001 && (num1-num2<0.0000001))
            return true;
        else
            return false;
     }
     public static double PowerAlthmn(double base,int exponent){
         double result1=1.0;
         while(exponent!=0){
             result1=result1*base;
             exponent--;
         }         
         return result1;
     }
}