PHP：關鍵字const、final、static

關鍵字:

1.const

#修飾屬性

**

<?php
class Person{
	public $name;
	const HOST='localhost';

	public function __construct($sn){
		$this->name=$n;
	}

	public function say(){
		echo "<p>my name is {$this->name}</p>";
	}
}

echo Person::HOST;
?>
           

**

localhost
           

2.final

#修飾類或方法

final最終版本

<?php
final class Person{
	public $name;
	const HOST='localhost';

	public function __construct($sn){
		$this->name=$n;
	}

	public function say(){
		echo "<p>my name is {$this->name}</p>";
	}
}

class IT extends Person{
	
}
?>
           

final最終方法

<?php
class Person{
	public $name;
	const HOST='localhost';

	public function __construct($sn){
		$this->name=$n;
	}

	final public function say(){
		echo "<p>my name is {$this->name}</p>";
	}
}

class IT extends Person{
	public function say(){
		
	}
}
?>
           

3.static

#修飾屬性或方法

static修飾屬性

<?php
class Person{
	public $name;
	static public $num;

	public function __construct($n){
		$this->name=$n;
		Person::$num++;
	}

	public function say(){
		echo "<p>my name is {$this->name}</p>";
	}
}

$obj=new Person('user1');
$obj2=new Person('user2');
$obj3=new Person('user3');
$obj4=new Person('user4');
$obj5=new Person('user5');
$obj6=new Person('user6');

echo Person::$num;
?>
           

static修飾方法

<?php
class Person{
	public $name;

	public function __construct($n){
		$this->name=$n;
	}

	public function say(){
		echo "<p>my name is {$this->name}</p>";
	}
	static public function sum($i,$j){
		return $i+$j;
	}
}
echo Person::sum(5,20);
?>