Question about using class Scanner

Question

Hi, everyone. I am a newbie of Java. I am writing a simple program to let user input 3 integers by using Scanner.
I know Scanner will igrone if more than 3.
But if i want to tell user if they were wrong when they input more than 3 integers,
is it possible if just use nextInt() to read?
Thank you!
Edited by: AlexChanMC on Feb 21, 2010 12:44 PM

Answer 1

AlexChanMC wrote:
javadoc said hasNext and next methods may block waiting for further input
that is why after i input 3 integers press enter and without response, then i need to input 4th thing to continue?
so how can i make the program response normally (print out) after input 3 integers and pressing enter and tell user they are wrong if they input 4 integers?
Edited by: AlexChanMC on Feb 21, 2010 5:39 PMHmmm. I don't think I've ever used a Scanner to read from the standard input ... usually, from files, like so:
      Scanner sc = new Scanner(new File("myNumbers"));
      while (sc.hasNextLong()) {
          long aLong = sc.nextLong();
      }Perhaps you can just get the whole line, and see if it matches the regular expression
"^(\\d+) (\\d+) (\\d+)$" // may need to trim the input line firstIf not, you don't have exactly three integers. That way, you only do a single nextLine() on the scanner.
{?