详解PHP中__construct()构造方法

<?php
class People{
    public $name;
    private $sex;
    protected $height;

    public function __construct(){
        echo "Knowledge is power!";
    }
    
    public function Hello(){
        echo "你好，世界!";
    }
}
//new People;        两者差别在于是否有参数
$man =new People();//构造方法自动调用
echo "<br>";
$man->Hello();//普通方法手动调用

输出：Knowledge is power!
      你好，世界!

<?php
class People{
    public $name;
    private $sex;
    protected $height;

    public function __construct($name){
        echo $name."say："."Knowledge is power!";

    }
}
$man =new People("张三");

输出：张三say：Knowledge is power!