PHP OOP，如何正确使用函数参数

我有一个小问题，我将解释代码下的所有内容：

<?php
class Fighter {
    public $name;
    public $health = 100;
    public $power;
    public $mainhand;

    public function Punch($enemy) {
        $arm = rand(0, 1);
        if($this->mainhand == "R") {
            if($arm == 1) {
                $this->power = $this->power * 2;
            }
        }
        else if($this->mainhand == "L") {
            if($arm == 0) {
                $this->power = $this->power * 2;
            }
        }

        switch($arm) {
            case 0:
                $arm = "left";
                $this->power = rand($this->power - 2, $this->power + 2);
                echo $this->name . " hits " . $enemy . " with " . $arm . " arm and deals " . $this->power . " damage";
                break;
            case 1:
                $arm = "right";
                $this->power = rand($this->power - 2, $this->power + 2);
                echo $this->name . " hits " . $enemy . " with " . $arm . " arm and deals " . $this->power . " damage";
                break;
        }

    }
}

$fighter = new Fighter();
$fighter->name = "John";
$fighter->power = 7;
$fighter->mainhand = "R";

$enemy = new Fighter();
$enemy->name = "Matt";
$enemy->power = 6;
$enemy->mainhand = "L";

$fighter->Punch($enemy->name);
echo "<br>";
$enemy->Punch($fighter->name);
echo "<br><br>";

echo $fighter->name . " - " . $fighter->health . "HP";
echo "<br>";
echo $enemy->name . " - " . $enemy->health . "HP";

?>

但它不起作用，我会出错：

注意：尝试获取非对象的属性

警告：尝试分配非对象的属性

---

你知道如何让代码按我想要的方式工作吗？

如果你试图用

Punch

方法进行计算，问题是你调用

Punch

时没有传递

Fighter

对象。您正在传递字符串

$name

属性。所以使用

$fighter->Punch($enemy);

而不是

$fighter->Punch($enemy->name);

如果您传递的是

Fighter

对象，那么您尝试使用的计算应该可以工作，但是您需要对

Punch

方法中的输出进行一些调整，例如，使用

$敌军->name

而不是

$敌军

echo $this->name . " hits " . $enemy->name . " with " . $arm . " arm and deals " . $this->power . " damage";
//     access the name property here ^^  since $enemy is no longer a string

如果您这样做是偶然的，那么您可以通过在方法签名中键入提示来在将来更早地发现错误

public function Punch(Fighter $enemy) {...

---

当我这样做时，我得到了错误：可捕获致命错误：类战斗机的对象无法转换为stringReplace

$Foreign

，在

echo

中使用

$Foreign->name

以后，您应该指出导致错误的行。行号在错误消息中。

public function Punch(Fighter $enemy) {...