What is the difference between accessing a parent class variable in PHP OOP using protected vs public?

When accessing a parent class variable in PHP OOP, using `protected` allows the variable to be accessed by child classes, while using `public` makes the variable accessible even outside the class hierarchy. If you want the variable to be accessible only to child classes, use `protected`. If you want the variable to be accessible outside the class hierarchy, use `public`. 

class ParentClass {
    protected $protectedVar = 'I am a protected variable';
    public $publicVar = 'I am a public variable';
}

class ChildClass extends ParentClass {
    public function getProtectedVar() {
        return $this->protectedVar;
    }

    public function getPublicVar() {
        return $this->publicVar;
    }
}

$child = new ChildClass();
echo $child->getProtectedVar(); // Output: I am a protected variable
echo $child->getPublicVar(); // Output: I am a public variable

Keywords

PHP OOP parent class variable protected public

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