Question

<?php
 //5.2.6
class Sample {
    private function PrivateBar() {
      echo 'private called<br />';
    }

    public static function StaticFoo() {
      echo 'static called<br />';
      $y = new Sample();
      $y->PrivateBar();
    }
 }

 Sample::StaticFoo();
?>

The above code will output:

"static called
 private called"

Why does $y->PrivateBar(); not throw an error? It is a private function after all.

What is the object oriented design logic behind this? Is this unique to PHP, or is this standard OOP?

Answer 1

Because StaticFoo, though static, is still considered part of the Sample class.

This is also reproducable in C#:

public class Sample
{
    private void PrivateBar()
    {
        Console.WriteLine("private called\r\n");
    }

    public static void StaticFoo()
    {
        Console.WriteLine("static called\r\n");
        Sample y = new Sample();
        y.PrivateBar();
    }
}

class Program
{
    static void Main(string[] args)
    {
        Sample.StaticFoo();
        Console.Read();
    }
}

With the output:

static called

private called