public class ReadDoubleTest // shows how to read a double the hard way { public static void main(String[] args) { System.out.println ("Enter a number, I'll add two to it."); double x; // the number we wish to read try { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); String s = br.readLine(); DecimalFormat df = new DecimalFormat(); Number n = df.parse(s); x = n.doubleValue(); } catch(IOException e) { x = 0; } catch(ParseException e) { x = 0; } System.out.println(x + 2); } }
thanks ChDw(米) try { Integer.parseInt(line); } catch(NumberFormatException e ) { //不是全数字 }you are right
// shows how to read a double the hard way
{ public static void main(String[] args)
{ System.out.println
("Enter a number, I'll add two to it.");
double x; // the number we wish to read
try
{ InputStreamReader isr
= new InputStreamReader(System.in);
BufferedReader br
= new BufferedReader(isr);
String s = br.readLine();
DecimalFormat df = new DecimalFormat();
Number n = df.parse(s);
x = n.doubleValue();
}
catch(IOException e)
{ x = 0;
}
catch(ParseException e)
{ x = 0;
}
System.out.println(x + 2);
}
}
try {
Integer.parseInt(line);
}
catch(NumberFormatException e ) {
//不是全数字
}you are right