Где тут ошибка?

class time
{
private:
	int hours, mins, secs;
public: 
	time() : hours(0), mins(0), secs(0) {}
	time(int h, int m, int s) : hours(h), mins(m), secs(s) {}
	void display()const {cout << "timesum: " << hours << ':' << mins << ':' << secs << endl;}
	void timesum(time t1, time t2)
	{
		secs = t1.secs + t2.secs;
		if(secs > 59) {secs -=60; mins++;}
		mins +=t1.mins + t2.mins;
		if(mins > 59) {secs -=60; hours++;}
		hours +=t1.hours + t2.hours;
	}
};
int main()
{
	const time t1(5,59,59);
	const time t2(2,43,22);
	time tsum;
	tsum.timesum(t1,t2);
	tsum.display();
	system("pause");
	return 0;
}