php自訂函數間的值傳遞/引用傳遞用法詳解

php:函數間的參數傳遞

1.值傳遞

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

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輸出結果：
1
In Exam: 2
1
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2.引用傳遞

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

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輸出結果：
1
In Exam: 2
2
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3.選擇性參數

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

輸出結果：
Total Price: 125
Total Price: 100
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4.如果傳入的是一個對象，可以更改該對象的值
（實際上變數$obj記錄的是這個對象的控制代碼，將$obj作為參數傳入，完全可以對原對象進行操作。）

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

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輸出結果：
Mr. zhan 12 male
Mr. zhan 13 male
Mr. zhan 14 male