我有两个文件：
ParentClass.php
<?php
class ParentClass {
public $variable1;
public $variable2 = "Value of variable 2";
public function __construct()
{
$this->variable1 = "Value of variable 1";
}
}
$obj = new ParentClass;
?>
和ChildClass.php
<?php
include "ParentClass.php";
class ChildClass extends ParentClass {
public function __construct()
{
echo $this->variable1;
echo $this->variable2;
}
}
$obj = new ChildClass;
?>
当我在浏览器中运行ChildClass文件时，它只给我变量2的值。它不显示变量1的值。我需要同时打印variable1和variable2值。请帮忙。