用JAVA 语言编译计算器

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Mycount
{
public static void main(String[] args)
{
int a=0;
double x=0;
double y = 0;
System.out.println("please enter the first value:");
InputStreamReader isrOfx=new InputStreamReader(System.in);
BufferedReader brOfx=new BufferedReader(isrOfx);
while (a == 0)
{
try
{
x = Double.parseDouble(brOfx.readLine().toString());
a++;
}
catch (Exception e)
{
System.out.println("please enter valid value:");
}
}
System.out.println("please enter the second value:");

InputStreamReader isrOfy=new InputStreamReader(System.in);
Buffe