php统计在线人数案例代码
php统计在线人数案例代码<?php
class Student{
private static $num=0;
public function __construct(){
self::$num++;
}
public function __destruct(){
self::$num--;
}
public function show(){
echo '总人数是:'.self::$num;
}
}
$stu = new Student;
$stu1 = new Student;
$stu->show();
?>注意:self表示所在类的类名,使用self降低耦合性
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