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 1 class Person
 2 {
 3     const HOST = 'localhost';
 4 
 5     public function say(){
 6         echo 'hello';
 7     }
 8 }
 9 
10 echo Person::HOST;

1 final class Person

2 {
3     const HOST = 'localhost';
4 
5     public function say(){
6         echo 'hello';
7     }
8 }

1 class Person
2 {
3     const HOST = 'localhost';
4 
5     final public function say(){
6         echo 'hello';
7     }
8 }

1.  1 class Person
    2 {
    3     public $name;
    4     static public $num;
    5 
    6     public function __construct($n){
    7         $this->name = $n;
    8         Person::$num++;
    9     }
   10 }
   11 new Person('user1');
   12 new Person('user2');
   13 new Person('user3');
   14 
   15 echo Person::$num; # 3

    1 # 
    2 
    3 class Person
    4 {
    5     public $name;
    6 
    7     public function __construct($n){
    8         $this->name = $n;
    9     }
   10 
   11     public function say(){
   12         echo "
   my name is {$this->name}
   ";
   13     }
   14 
   15     static public function sum($i,$j){
   16         return $i+$j;
   17     }
   18 }
   19 
   20 echo Person::sum(5,25);