找出N以内的所有“完数”（一个完数等于自己的因子之和，例如6=1＋2＋3），并将其值反序输出，N的初始值从命令行参数获取。

public clasee ExamDemo {

       static int reverse(int n, int v){

              return n == 0 ? v : reverse(n / 10, v * 10 + n % 10);

       }

       public static void main(String[] args){

              int m = 0, s = 0, i = 0, n;

              n = Integer.parseInt(arg[0]);

              for (m = 2; m < n; m++){

                     s = 0;

                     for (i = 1; i < m; i++){

                            if ((m % i) == 0)

                                   s += i;

                     }

                     if (s == m)

                            System.out.println(reverse(m, 0));      

              }

       }

}