What are the variable scope areas in PHP?

• Global: Variables declared outside functions or classes are accessible in the global scope. Inside functions, they need to be accessed using the global keyword or the superglobal array $GLOBALS.
• Local: Variables declared inside a function are only accessible within that function.
• Static: Variables declared with the static keyword inside a function retain their value between function calls.
• Function/Method parameters: Parameters passed to a function or method are only accessible within that function/method as local variables.
• Class properties: Class properties (declared with public, protected, private modifiers) are accessible within the context of an object of that class.

<?php
// Global scope
$globalVar = 'I am global';

function testScope() {
    // Local scope
    $localVar = 'I am local';

    // Accessing global variable using global keyword
    global $globalVar;
    echo $globalVar . "\n";

    // Accessing global variable using $GLOBALS
    echo $GLOBALS['globalVar'] . "\n";

    echo $localVar . "\n";
    // echo $staticVar; // Error: undefined variable
}

function testStatic() {
    // Static scope
    static $staticVar = 0;
    $staticVar++;
    echo "Static variable: " . $staticVar . "\n";
}

function testParameters($param) {
    // Parameter scope
    echo "Parameter: " . $param . "\n";
}

testScope();
testStatic(); // Output: Static variable: 1
testStatic(); // Output: Static variable: 2
testParameters('Hello');

class MyClass {
    public $publicProperty = 'I am public';
    protected $protectedProperty = 'I am protected'; // Accessible within the class and subclasses
    private $privateProperty = 'I am private';     // Accessible only within the class

    public function accessProperties() {
        echo $this->publicProperty . "\n";
        echo $this->protectedProperty . "\n";
        echo $this->privateProperty . "\n";
    }
}

$obj = new MyClass();
$obj->accessProperties();
// echo $obj->privateProperty; // Error: Cannot access private property
?>