PHP Learning note 0001 variable scope

<?php
/*
2015-8-6
PHP Learning Note 0001
Variables declared outside the function have Global scope and can only be accessed outside of the function.
Variables declared inside a function have a local scope and can only be accessed inside the function.
*/
$x = 5;
function AST ()
{
/*
Declaring local variables
Output is 6
*/
$x = 6;
echo $x;
}
function Beli ()
{
/*
No local changes declared
Global variables cannot be accessed inside a function
Compile normal call error
*/
echo $x;
}
AST ();//Output 6
Beli ();//Will Error
echo $x;//Output 5
?>

PHP Learning note 0001 variable scope