Differences between public, protected, and private and the use of __set () and __get ()

The difference between public, protected, and private

Public represents the global, and the inner and outer subclasses of the class can be accessed;

Protected is protected and is accessible only in this class or subclass or in the parent class;

Private means that only this class can be used internally;

Among them, public has global and inheritance; protected is inherited; private can only be used by this class, not global and inherited.

Usage of __set () and __get ()

If an external program wants to get a private property inside the class, such as a private $name, you can define a __get ($a) method in the class to manipulate the $name value and return it, and the external object can then get a processed private $name value through $test->name.

If an external program wants to operate on a private property inside a class, you can define a __set ($a, $b) method in the class to manipulate the private property, and the external object is then able to manipulate the $name property by $test->name= "value".

For example:

Class test{
    Private $name = "";

    function __construct () {
    $this->name= "Alice";
$this->age=20;
}
    

}
    function __set ($a, $b) {
        $this $a = $b;
    
}
$test =new test ();
echo $test->name. " <br> ". $test->age." <br> ";
$test->name= "ABCD";
Echo $test->name;
?>

The output is:

Alice

20

Abcd

Differences between public, protected, and private, and the use of __set () and __get ()