PHP语言 -- 面向对象和面向过程的区别

例子：求阴影面积

面向过程

$r1 = 20;
$r2 = 10;

$mj = 3.14*$ri*$ri-3.14*$r2*$r2;

echo $mj;

面向对象

class Yuan
{
    private $r;
    function __construct($r)
    {
    $this->r = $r
    }
    function Mj()
    {
    return 3.14*$this->r*$this->r;
    }
}


$yuan1 = new Yuan(20);
$yuan2 = new Yuan(10);
eho $yuan1->Mj()-$yuan2->Mj();