// Race2.java
// wyscig

class Counter {
  private int _val;
  public Counter(int n) {
	_val = n;
  }
  public void inc() {
	int n;
	n = _val;
	n = n + 1;
	//Thread.yield(); // !!! wymuszenie zmiany kontekstu !!!
	_val = n;
  }
  public void dec() {
	int n;
	n = _val;
	n = n - 1;
	_val = n;
  }
  public int value() {
	return _val;
  }
}

class IThread extends Thread {
  private Counter _cnt;
  public IThread(Counter c) {
	_cnt = c;
  }
  public void run() {
	for (int i = 0; i < 1000000; ++i) {
	  _cnt.inc();
	}
  }
}

class DThread extends Thread {
  private Counter _cnt;
  public DThread(Counter c) {
	_cnt = c;
  }
  public void run() {
	for (int i = 0; i < 1000000; ++i) {
	  _cnt.dec();
	}
  }
}

class Race2 {
  public static void main(String[] args) {
	Counter cnt = new Counter(0);
	IThread it = new IThread(cnt);
	DThread dt = new DThread(cnt);
	
	//it.setPriority(10);
	it.start();
	dt.start();
	
	try {
	  it.join();
	  dt.join();
	} catch(InterruptedException ie) { }
	
	System.out.println("value=" + cnt.value());
  }
}