php函数间的参数传递(值传递/引用传递)_php技巧

php:函数间的参数传递

1.值传递
代码如下:

<br><!--?php <BR-->function exam($var1){ <br>$var1++； <br>echo "In Exam:" . $var1 . "<br>"; <br>} <br><br>$var1 = 1; <br>echo $var1 . "<br>"; <br>exam($var1); <br>echo $var1 . "<br>"; <br>?> <br> <br>------------------------------------------------------------------------------- <br>

输出结果：
1
In Exam: 2
1
-------------------------------------------------------------------------------
2.引用传递
代码如下:

<br><!--?php <BR-->function exam( &$var1){ <br>$var1++； <br>echo "In Exam:" . $var1 . "<br>"; <br>} <br><br>$var1 = 1; <br>echo $var1 . "<br>"; <br>exam($var1); <br>echo $var1 . "<br>"; <br>?> <br> <br><br>------------------------------------------------------------------------------- <br>

输出结果：
1
In Exam: 2
2
-------------------------------------------------------------------------------
3.可选参数
代码如下:

<br>function values($price, $tax=""){ <br>$price += $prive * $tax; <br>echo "Total Price:" . $price . "<br>"; <br>} <br><br>values(100, 0.25); <br>values(100); <br> <br>

输出结果：
Total Price: 125
Total Price: 100
-------------------------------------------------------------------------------
4.如果传入的是一个对象，可以更改该对象的值
（实际上变量$obj记录的是这个对象的句柄，将$obj作为参数传入，完全可以对原对象进行操作。）
代码如下:

<br><!--?php <BR-->class Obj{ <br>public $name; <br>public $age; <br>public $gander; <br>public function __construct($name, $age, $gander){ <br>$this->name = $name; <br>$this->age = $age; <br>$this->gander = $gander; <br>} <br>public function show_info(){ <br>echo $this->name . " " . $this->age . " " . $this->gander . "<br>"; <br>} <br>} <br>function grow($obj){ <br>$obj->age++; <br>} <br>function test(){ <br>$obj = new Obj("Mr. zhan", "12", "male"); <br>$obj->show_info(); <br>grow($obj); <br>$obj->show_info(); <br>grow($obj); <br>$obj->show_info(); <br>} <br>test(); <br>?> <br> <br>------------------------------------------------------------------------------- <br>

输出结果：
Mr. zhan 12 male
Mr. zhan 13 male
Mr. zhan 14 male