访问控制

探究public , private , protected三种类型的数据的访问控制

其中public能被自身 ， 子类 ，外部 访问；

protected 能被自身和子类访问，不能被外部直接访问；

private 只能被自身访问，不能被子类和外部访问。

<?php

class Human{
    public $name;
    protected $height;  //只有自身和子类能被访问
    public $weight;
    private $isHungry = true;  //不能被子类访问

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

    public function info() {
        //通过自身调用private数据传到外部
        echo "HUMAN:".$this->name.";".$this->height.";".$this->isHungry ."<br/>";
    }
}


class NbaPlayer extends Human{
    
    public $team="Bull";
    public $playerNumber="23";

    private $age = "40";//private的类成员只能在内部被访问

    function __construct($name,$height,$weight,$team,$playerNumber) {
        echo "In NbaPlayer constructor"."<br/>";
        $this->name = $name; 
        $this->height = $height;
        $this->weight = $weight;
        $this->team = $team;
        $this->playerNumber = $playerNumber;
      //  echo $this->isHungry."<br/>";  调用出错
    }

    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/>";
    }

    public function getAge() {  //通过子类调用protected的数据，传到外部访问
        //外部不能直接访问，所以可以在内部对数据进行改动，使外部不能得到真实数据
        echo $this->name."'s age is ".($this->age-2) ."<br/>";  
    }
}

$jordan = new NbaPlayer("Jordan","198cm","98kg","Bull","23");
 $jordan->getAge() ."<br/>";
 //$jordan->height;  直接访问height会出错

 $jordan->info();