我試圖在擴(kuò)展類中使用顯示函數(shù)，該類首先在父類中獲取顯示函數(shù)。但是，它不會在echo語句中顯示變量。游戲類型（在這種情況下為“一日”）不會顯示。<?phpclass Cricket{    protected $gameType;    function __construct($gameType)    {        $this->gameType=$gameType;    }    function display()    {        echo 'The cricket match is a ' . $this->gameType . " match";    }}class Bowler extends Cricket{    public $type;    public $number;    function __construct($type,$number)    {        $this->type=$type;        $this->number=$number;        parent::__construct($this->gameType);    }    function display()    {        parent:: display();        echo " with " . $this->number . " " . $this->type . " bowler";    }}   $one = new Cricket("day-night");$one->display();echo'<br>';$two  = new Cricket("day-night");$two = new Bowler("left-hand","2");$two->display();?>