我如何从另一个PHP文件中引用变量? [关闭]

Let's say: in file Cat.php, I made a variable called $Kitty. On the other hand, I have another file called Dog.php. Now I wanna echo the variable $Kitty in the file Dog.php, how do I do that?

This is my code in the Dog.php file:

<!DOCTYPE html>

<html>
<body>
<?php include 'cat.php';
echo $kitty;
?>
</body>
</html>

Use include, like this:

<?php

  include('Cat.php');

  echo $Kitty

?>

You can use the session variable. in cat.php

<?php
session_start();
$_SESSION['cat']=$Kitty;
?>

Now in dog.php

    <?php
    session_start();
    echo $_SESSION['cat'];
session_destroy();
    ?>