/**
 * Construct a scenario in which the loop in Thread0 executes exactly once.
 * 
 * Construct a scenario in which the loop in Thread0 executes exactly three
 * times.
 * 
 * Construct a scenario in which the loop in Thread0 executes exactly
 * infinitely often.
 */
public class Example1 {

    public static void main (String args[]) {
        
        Flag globalflag = new Flag();
        Thread t0 = new Thread(new Thread0(globalflag));
        Thread t1 = new Thread(new Thread1(globalflag));;
        t0.start();
        t1.start();
    }
}

class Thread0 implements Runnable {

    Flag f; 

    Thread0 (Flag globalflag) {
        f = globalflag;
    }

    public void run() {

        while (f.flag < 1) {
            f.flag++;
        }
    }
}

class Thread1 implements Runnable {

    Flag f; 

    Thread1 (Flag globalflag) {
        f = globalflag;
    }

    public void run() {

        while (f.flag >= 0 ) {
            f.flag--;
        }
    }
}

class Flag {
    volatile int flag = 1;
}