#include <sys/time.h>

class stopwatch {
	private:
		timeval start_time;
		float elapsed;
		bool running;

	public:
	stopwatch() {
		elapsed = 0.0;
		running = false;
	}
	
	void start() {
		gettimeofday(&start_time, NULL);
		running = true;
	}

	float stop() {
		timeval end_time, elapsed_time;
		gettimeofday(&end_time, NULL);
		
		timersub(&end_time, &start_time, &elapsed_time);
		elapsed = elapsed_time.tv_sec + (elapsed_time.tv_usec/1000000.0);
		running = false;
		return elapsed;
	}

	float read() {
		return elapsed;
	}

	bool isRunning () {
		return running;
	}
};