How to get the ID of the link in another page in php

PHP Snippet 1:

<a href="show.php?ref=<?php 
  echo htmlspecialchars(urlencode($row['name']));
?>&id=<?php 
  echo htmlspecialchars(urlencode($id));
?>" 
id="<?php 
  echo htmlspecialchars($id);
?>"><?php 
  echo htmlspecialchars($id) . '.' . htmlspecialchars($row['name']); 
?></a>

PHP Snippet 2:

<?php

   //show.php?ref=5&id=10

   echo $_GET['ref'];
   //5

   echo $_GET['id'];
   //10

?>

PHP Snippet 3:

<?php echo $_GET["id"]; ?>