继承

<?php

class Human{
    public $name;
    public $height;
    public $weight;

    public function eat($food) {
        echo $this->name." is eating ".$food."<br/>";
    }
}

//php中可以使用extends关键字表示类的继承，后面跟父类的类名
//php中extends后面只能跟一个类的类名，这就是php的单继承原则
class NbaPlayer extends Human{
    
    public $team="Bull";
    public $playerNumber="23";

    function __construct($name,$height,$weight,$team,$playerNumber) {
        echo "In NbaPlayer constructor"."<br/>";
        $this->name = $name;  //父类中的属性可以用this 来访问
        $this->height = $height;
        $this->weight = $weight;
        $this->team = $team;
        $this->playerNumber = $playerNumber;
    }

    function __destruct() {
        echo "Destroying".$this->name."<br/>";
    }

    //方法定义
    public function run() {
        echo "Running"."<br/>";
    }

    public function jump() {
        echo "Jumping"."<br/>";
    }
    public function dribble() {
        echo "Dribbling"."<br/>";
    }
    public function shoot() {
        echo "shooting"."<br/>";
    }
    public function dunk() {
        echo "Dunking"."<br/>";
    }
    public function pass() {
        echo "passing"."<br/>";
    }
}

$jordan = new NbaPlayer("Jordan","198cm","98kg","Bull","23");
echo $jordan->name."<br/>";

$jordan->eat("apple");//在子类的对象上可以直接访问父类的属性和方法

注意，在NbaPlayer()中是没有name,height,weight这些属性的，这些都是在父类中的属性，但通过继承后

可以成为子类NbaPlayer()中的属性

输出结果：

In NbaPlayer constructor
Jordan
Jordan is eating apple
DestroyingJordan