Why is this still 2 after using the constructor?

Why is the result 2 instead of 5?

<code>class a{
    public $age=2;
    public function __constrator(){
       $this->age=$age+3;
    }
    
}

$k=new a();
echo $k->age;</code>

Reply content:

Why is the result 2 instead of 5?

<code>class a{
    public $age=2;
    public function __constrator(){
       $this->age=$age+3;
    }
    
}

$k=new a();
echo $k->age;</code>

It made me laugh __constrator became __construct and $this->age=$this->age+3;

<code>class a{
    public $age=2;
    public function __constrator(){
       $this->age=$this->age+3; // 这里
    } 
    
}

$k=new a();
echo $k->age;</code>

This one is missing $this->

<code> $this->age=$this->age+3;</code>