readdouble.java

Java程序

import  java.io.* ;
public class ReadDouble
{  public static Double read(String a)
   {try
    {return Double.parseDouble(a);}
    catch(NumberFormatException e)
    {System.out.println("输入错误，请重新输入");
     double bb=read(input());
     return bb;}
   }
   public static String input()
    {String strinfo=null;
       try
      {BufferedReader  br =new BufferedReader(new InputStreamReader(System.in));
       strinfo=br.readLine();}
       catch (IOException  e)
      {System.out.println("caught IOException");}
      return strinfo;
    }
 public static void main(String[] args)
     { double aa=read(input());
     System.out.println(aa);}
 }