$a = (($year-1)+(int)(($year-1)/4)-(int)(($year-1)/100)+(int)(($year-1)/400)+$day_num)%7;
$year是指具體是哪一年,$day_num指這一天是該年的哪一天.計算出的結果:從0到6,分別表示星期日到星期六.
$a = (($year-1)+(int)(($year-1)/4)-(int)(($year-1)/100)+(int)(($year-1)/400)+$day_num)%7;
$year是指具體是哪一年,$day_num指這一天是該年的哪一天.計算出的結果:從0到6,分別表示星期日到星期六.