访问类中私有/受保护变量的正确方法（PHP）

Question

What is the proper way of accessing private/protected variable in a class in PHP?

I learned that it can be access using __construct function. Ex.

class helloWorld
{
    public $fname;
    private $lname;
    protected $full;
    function __construct()
    {
        $this->fname = "Hello";
        $this->lname = "World";
        $this->full = $this->fname . " " . $this->lname;
    }
}

Or create a Getter or Setters function. I don't know if that's the right term.

class helloWorld
{
    public $fname;
    private $lname;
    protected $full;

    function getFull(){
        return $this->full;
    }

    function setFull($fullname){
        $this->full = $fullname;
    }

}

or via __toString. I'm confuse o what should I use. Sorry, I'm still new to OOP. Also what is :: symbol in php and how can I use it?

Thanks :)

Answer 1

:: operator is called the scope resolution operator. It has a no.of use case.

1.Can be used to refer static variables or function of a class . the syntax is class name::variable_name Or class name::function_name() . This is because static variables or functions are referenced through class names .

2.It can also be used for function overriding. You can understand it with an example

class Base
{
    protected function myFunc() {
        echo "I am in parent class 
";
    }
}

class Child extends Base
{
    // Override parent's definition
    public function myFunc()
    {
        // But still call the parent function
        Base::myFunc();
        echo "I am in the child class
";
    }
}

$class = new Child();
$class->myFunc();

This is useful when you want your parent function to be executed first and then your child function.

3.It is also used to refer the variables or functions within a class itself through self::$variable_name OR self::function_name() . Self is used to refer to the class itself.