//BinaryOutputDemo.java

import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.io.FileNotFoundException;
import java.io.File;
import java.io.IOException;
import java.util.Scanner;

public class BinaryOutputDemo
{
    public static void main(String[] args)
    {
        String fileName = "numbers.dat";
        try
        {
            ObjectOutputStream outputStream =
                new ObjectOutputStream(new FileOutputStream(fileName));
            Scanner keyboard = new Scanner(System.in);
            System.out.println("Enter nonnegative integers.");
            System.out.println("Place a negative number at the end.");

            int anInteger;
            do
            {
                anInteger = keyboard.nextInt();
                outputStream.writeInt(anInteger);
            }
            while (anInteger >= 0);
            System.out.println("Numbers and sentinel value");
            System.out.println("written to the file " + fileName);
            outputStream.close();
        }
        catch (FileNotFoundException e)
        {
            System.out.println("Problem opening the file " + fileName);
        }
        catch (IOException e)
        {
            System.out.println("Problem with output to file " + fileName);
        }
    }
}