import java.util.Scanner;

/** Error4.java - More error checking of user input.  A more serious kind
 *  of input error is when the type of input is unexpected.  For example,
 *  we ask for a number and we get a string.
 */
public class Error4
{
  public static void main(String [] args)
  {
    Scanner kbd = new Scanner(System.in);

    // We need to declare the input variable before the loop and try/catch.
    int n = 0;

    boolean needInput = true;
    while (needInput)
    {
      System.out.print("Please enter an integer:  ");

      // If the user enters a string, we get a NumberFormatException.
      // It's good to put as little code in the try/catch as possible.
      // Only put the risky code in the try part.
      try
      {
        n = Integer.parseInt(kbd.nextLine());
      }
      catch (NumberFormatException e)
      {
        System.out.println("Sorry, I don't understand.  Try again.");
        continue;
      }

      // If we get this far, the input is okay.
      needInput = false;
    }

    System.out.println("You entered " + n);
  }
}