​x
 
<!DOCTYPE html>
<html>
<body>
​
<?php
$x=17; 
echo ++$x;
echo "<br>";
​
$y=17; 
echo $y++;
echo "<br>";
​
$z=17;
echo --$z;
echo "<br>";
​
$i=17;
echo $i--;
?>   
​
</body>
</html>
​