利用条件运算符的嵌套来完成此题：学习成绩> =90分的同学用A表示，60-89分之间的用B表示，60分以下的用C表示。

 1 
 2 
 3 import java.io.*;
 4 
 5 public class RankOfScore3 
 6 {
 7         public static void main(String[] args)
 8         {
 9                 String s = "",rank = "";
10                 try
11                 {
12                         BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
13                         s = in.readLine();
14                 }
15                 catch(IOException e)
16                 {}
17                 double score = Double.parseDouble(s);
18                 
19                 rank = score >= 60 ? (score >= 90 ? "A" : "B") : "C";
20                 System.out.println(rank);
21         }
22 }