CODE RESULTS
$a = floor(3.5); //3
$b = round(3.5, 0, PHP_ROUND_HALF_DOWN); //3
var_dump($a); //float(3)
var_dump($b); //float(3)
$c = gettype($a); //double
$d = gettype($b); //double
有什么区别。?我何时使用floor()或round()作为上面的数字。?