if (hour<10)  {System.out.printf("0%d:",hour);}
        else {System.out.printf("%d:",hour);}
        if (min<10)  {System.out.printf("0%d:",min);}
        else {System.out.printf("%d:",min);}
        if (sec<10)  {System.out.printf("0%d",sec);}
        else {System.out.printf("%d",sec);}