$maxLine = 4;
$no = 17;
$line = ceil($no/$maxLine); 进行除法运算后得数是咋算的 得数不是4吗??
17/4向上取整,就得到5了,ceil是向上取整!!!
floor向下取整e.g.
floor(1.9)=1
ceil向上取整e.g.
ceil(1.1)=2