C语言 格式化输出

sprintf(hour1,"%02d",(int)(time1[i] / 3600));
sprintf(minute1, "%02d", (int)((time1[i] - ((int)(time1[i] / 3600))*3600 )/60));
sprintf(second1, "%06.3f", (time1[i] - ((int)(time1[i] / 60))*60));
sprintf(time2[i], "%s:%s:%s", hour1, minute1, second1);