----------------------------------- Code 1 -----------------------------------
echo ("Testing") ;

----------------------------------- Code 2 -----------------------------------
echo "Testing" ; // () is not necessary in echo

----------------------------------- Code 3 -----------------------------------
echo <<<END
 Hello world . 
 <br> <i> Hello . </i>
END;

----------------------------------- Code 4 -----------------------------------
print ("Testing") ; 

----------------------------------- Code 5 -----------------------------------
define ("CONSTANT", "Hello world.") ;
print CONSTANT ;

----------------------------------- Code 6 -----------------------------------
$a = array('5', '10', '15', '20') ; // Defining an array
print_r ($a) ; // print all array elements

----------------------------------- Code 7 -----------------------------------
echo ("<pre>") ; // <pre> is an HTML code : to show the result more readable
print_r ($GLOBALS) ; // $GLOBALS is a predefinrd array style variable

----------------------------------- Code 8 -----------------------------------
highlight_file ("php.php") ; // Print out entire file in highlight mode