阶乘倒数的和

 1 package jiecheng;
 2
 3 public class ted {
 4
 5     public static void main(String[] args) {
 6
 7          double tex = 0,a = 1;
 8           int i = 1;
 9           while(i <= 20)
10           {
11               tex = tex+a;
12               i = i+1;
13               a = a*(1.0/i);
14           }
15           System.out.println(tex);
16
17     }
18
19 }

   用 while语句输出阶乘倒数的和