程序片段--2的乘方

 1 public class Sum2 {
 2     final static  int count =2;
 3     //输入2的次方，获得2的次方的结果
 4     public static int sum2(int loop){
 5         int result=1;
 6         if(loop<0){
 7             return 1;
 8         }else{
 9             while(loop>0){
10                 result*=count;
11                 loop--;
12             }  
13         }
14               
15         return result;
16     }
17     //输入2的倍数，获得2的次方数
18     public static int sum3(int result){
19         int ct=0;
20         if(result % count != 0 || result<0){
21             System.out.print("error = ");
22             return result;
23         }else{
24             while(result != 1){
25                 result /= count ;
26                 ct++;
27             }
28         }         
29         return ct;
30     }
31     public static void main(String[] args) {
32         System.out.println(sum2(4));
33         System.out.println(sum3(16));
34     }
35 }