oop-private-parameters

<?php

ini_set('display_errors', 1); 
ini_set('display_startup_errors', 1); 
error_reporting(E_ALL);

class Car {

	private $color = 'White';

	public function setColor($color)
	{
		$this->color = $color;
	}

	public function getColor()
	{
		return $this->color;
	}

}

$car = new Car();
echo $car->color;			// Return Fatal Error: Cannot access private property
echo $car->getColor();			// Return White. The function getColor() is public.

$car->setColor('Yellow');
echo $car->getColor();			// Return Yellow. The function getColor() is public.

////////////////////////////////////////////////////////////////

class Beetle extends Car {



}

$beetle = new Beetle();
echo $beetle->color;			// Notice: Undefined property. The parent property keeps in it.
echo $beetle->getColor();		// Return White. The function getColor() is public.

$beetle->setColor('Green');
echo $beetle->getColor();		// Return Green. The function getColor() is public.

////////////////////////////////////////////////////////////////

class Ferrari extends Car {

	private $color = 'RedFerrari';

	// public function getColor()
	// {
	// 	return $this->color;
	// }

}

$ferrari = new Ferrari();
echo $ferrari->color;			// Return Fatal Error: Cannot access private property
echo $ferrari->getColor();		// Return White. The function getColor() is public.

$ferrari->setColor('Red');
echo $ferrari->getColor();		// return Red