//In .h
class timer_s {
	int interval;
	int end_time;
	bool repeat;
	bool finished;
public:
	timer_s(int interval, bool repeat);
	bool done();
};

//In .cpp
timer_s::timer_s(int interval, bool repeat) : interval(interval), repeat(repeat) {
	end_time = ::time(NULL) + interval;
}
bool timer_s::done() {
	bool done = ::time(NULL) >= end_time && !finished;
	if (done) {
		if(repeat) end_time = ::time(NULL) + interval;
		else finished = true;
	}
	return done;
}

//Usage
while (true) {
	static timer_s timer(1, true);
	if (timer.done()) {
		//will print "done" every 1 second
		cout << "done" << endl;
	}
}