<?php
/**
 * 定义接口
 */
interface car{
    public function run();
}

/**
 * 接口算法实现
 * @return [type] [description]
 */
class bmwCar implements car{
    public function run(){

        echo "宝马汽车在路上奔驰\n";
    }
}

/**
 * 接口算法实现
 * @return [type] [description]
 */
class audiCar implements car{
    public function run(){

        echo "奥迪汽车在路上奔驰\n";
    }
}

/**
 * 使用不同算法的类
 * @param integer $speed [description]
 */
class chooseCar{
    public $speed;

    function __construct($speed=60){
        $this->speed = $speed;

    }

    function start($brand){
        $car = null;

        switch($brand){
            case "bmw":
                $car = new bmwCar();
                break;
            case "audi":
                $car = new audiCar();
                break;
            default:
                $car = new bmwCar();
        }
        $car->run();
        echo "时速为{$this->speed}km/h";
    }
}

$car = new chooseCar(180);
$car->start("audi");

//输出
奥迪汽车在路上奔驰 时速为180km/h