<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>多态性</title>
</head>
<body>
<?php
abstract class Car{ //注意类名和函数名都要加abstract
abstract public function say();
}
class Taxi extends Car{
public function say(){
echo "出租车"."<br>";
}
}
class Bus extends Car{
public function say(){
echo "公交车"."<br>";
}
}
function say($obj ){
if($obj instanceof Car){
$obj->say();
}
}
$taxi=new Taxi();
$bus=new Bus();
say($taxi); //输出"出租车"
say($bus); //输出"公交车"
?>
</body>
</html>