Differences between passing references in PHP array object values

The general data types (INT, float, bool) are not described in this regard.

Here we will introduce in detail the differences between the array and the class object passing values as parameters.

Array value transfer

Instance code:

<?phpfunction main() {        $cc = array(            'a','b'        );        change($cc);        var_dump($cc);        die;}function change($cc){        $cc = array('dd');}main();?>output:array(2) {  [0]=>  string(1) "a"  [1]=>  string(1) "b"}

Array reference Transfer

<?phpfunction main() {        $cc = array(            'a','b'        );        change($cc);        var_dump($cc);        die;}function change(&$cc){        $cc = array('dd');}main();?>outpout:array(1) {  [0]=>  string(2) "dd"}

 

Class Object value transfer

<?phpclass pp{        public $ss = 0;}function main() {        $p = new pp();        change($p);        var_dump($p);        die;}function change($p){        $p->ss = 10;}main();?>output:object(pp)#1 (1) {  ["ss"]=>  int(10)}

Class Object Reference Transfer

<?phpclass pp{        public $ss = 0;}function main() {        $p = new pp();        change($p);        var_dump($p);        die;}function change(&$p){        $p->ss = 10;}main();?>object(pp)#1 (1) {  ["ss"]=>  int(10)}

 Summary: in PHP, an array is a common variable. Passing a value requires a copy of a real parameter, which is irrelevant to the real parameter. After passing a reference, the value of the real parameter can be changed.
The object of the class is a reference transfer for both value passing and reference passing. It is a reference to the object and changes the value of the real parameter.