PHP面向对象开发之类的多态详解

class A {}
class B {}

$thing = new A;
if ($thing instanceof A) {
echo "A";
}
if ($thing instanceof B) {
echo "B";
}

class A {

}

class B {

}

$new = new A;

if ($new instanceof A) {
echo "A";
}
if ($new instanceof B) {
echo "B";
}
?>

interface MyUsb {
 function type();
 function alert();
}

class Zip implements MyUsb {
 function type() {
  echo "2.0";
 }
 function alert() {
  echo "U盘驱动正在检测……
";
 }
}

class Mp3 implements MyUsb {
 function type() {
  echo "1.0";
 }
 function alert() {
  echo "MP3驱动正在检测……";
 }
}

class MyPc {
 function Add_Usb($what) {
  $what->type();
  $what->alert();
 }

}
$p = new MyPc();

$zip = new Zip();

$mp3 = new Mp3();

$p->Add_Usb($zip);
$p->Add_Usb($mp3);
?>