Internal Function Variables in PHP

Variables declared inside a function are not visible outside. Let's look at an example. Suppose we have the following variable:

<?php
	function func()
	{
		$num = 1;
	}
?>

Let's try to output the variable $num from outside the function:

<?php
	function func()
	{
		$num = 1;
	}
	
	func();
	echo $num; // error
?>

Explain what the result of the code execution will be:

<?php
	function func()
	{
		$aaa = '!!!';
	}
	
	func();
	echo $aaa;
?>

Explain what the result of the code execution will be:

<?php
	function func($aaa)
	{
		$aaa = 222;
	}
	
	func(111);
	echo $aaa;
?>