import java.util.Scanner;

/**
 Illustrates the use of a boolean variable to end loop iteration.
*/
public class BooleanDemo
{
    public static void main(String[] args)
    {
        System.out.println("Enter nonnegative numbers.");
        System.out.println("Place a negative number at the end");
        System.out.println("to serve as an end marker.");
        int sum = 0;
        boolean areMore = true;
        Scanner keyboard = new Scanner(System.in);
        while (areMore)
        {
            int next = keyboard.nextInt( );
            if (next < 0)
                areMore = false;
            else
                sum = sum + next;
       }
	   System.out.println("The sum of the numbers is " + sum);
    }
}