a counter as timer which has states start, stop, is expired

++
// C++
class Counter {
  private:
    int _startTime;
    int _stopTime;

  public:
    void start() {
      _startTime = time(NULL);
    }

    void stop() {
      _stopTime = time(NULL);
    }

    bool isExpired(int duration) {
      return _stopTime - _startTime > duration;
    }
}