【Java】設計一個簡單的計算器，實現加減乘除運算並輸出結果

import java.io.*;
import java.util.*;
public class Test
{  
   public static void main(String[] args) throws IOException
   {     
      double x,y,z=0;
      char ch;
      Scanner rd=new Scanner(System.in);
      BufferedReader buf =new BufferedReader(new
                                       InputStreamReader(System.in));    
      System.out.println("請輸入X，Y：");
      x=rd.nextDouble();
      y=rd.nextDouble();
      System.out.println("請輸入運算符：");
      ch=(char)buf.read();
      switch(ch)
      {
         case'+':z=x+y;break;
         case'-':z=x-y;break;
         case'*':z=x*y;break;
         case'/':z=x/y;break;
         default:System.out.println("輸入的運算符不正確哦！");
      }
      System.out.println("運算結果是："+z);
   }
}