整数的整数次方

 1 　　public double Power(double base, int exponent){
 2         double result = 1;
 3         if(exponent==0)
 4             return 1;
 5         if(equal(base,0.0))
 6             return 0;
 7         if(exponent>0){
 8             for(int i=0;i<exponent;i++){
 9                 result *= base;
10             }
11         }
12         else{
13             exponent = -exponent;
14             for(int i=0;i<exponent;i++){
15                 result *=base;
16             }
17             result = 1/result;
18         }
19         return result;
20     }
21     //注意double类型的比较
22     public boolean equal(double num1, double num2){
23         if((num1-num2)>-0.0000001 && (num1-num2)<0.0000001)
24             return true;
25         else
26             return false;
27     }