 php  ,       (), 
     . 
 
<?php 
$q=($w=1)+1; 
print $q; 
exit; 
?>.

 :

<?php
$q=1;
$q+=4;
if($q=5)
{
    print "Hello world!";
}
else
{
    print " q   5";
}
exit;
?>

   $q  4 "$q+=4;" 
   "  $q  5     hello world, 
  $q         " q   5" 
   "exit"     ".

 

<?php
$q="Hello";
$w= $q. " world!";
print $w;
exit;
?>

    $q  "world!".
