Question

I have tried various techniques to check the values of user input in this method. The user should only be able to enter a ‘1’ or a ‘0’. If any other input is used there should be an error message and the program exits. Any ideas? I got it to work for the first digit but not the second through the tenth.

    System.out.println("Enter a ten digit binary number.  Press 'Enter' after each digit.  Only use one or zero. :");

        binary[0] = keyboard.nextInt();

        for (index = 1; index < 10; index++)
            binary[index] = keyboard.nextInt();// fill array with 10 binary
                                                // digits from user. User
                                                // must press 'Enter' after
                                                // each digit.

Answer 1

Try this:

    Scanner scanner = new Scanner(System.in);
    if (scanner.hasNext())
    {
        final String input = scanner.next();
        try
        {
            int num = Integer.parseInt(input, 2);
        }
        catch (NumberFormatException error)
        {
            System.out.println(input + " is not a binary number.");
            //OR You may exit here, if you don't want to continue
        }
    }