// 定義一個(gè)函數(shù)來(lái)計(jì)算圓形的面積
function calculateCircleArea($radius) {
    return 3.14 * $radius * $radius;
}
// 定義一個(gè)函數(shù)來(lái)計(jì)算矩形的面積
function calculateRectangleArea($length, $width) {
    return $length * $width;
}
// 計(jì)算圓形的面積
$radius = 5;
$circleArea = calculateCircleArea($radius);
echo "圓形的面積：" . $circleArea . "\n";
// 計(jì)算矩形的面積
$length = 4;
$width = 6;
$rectangleArea = calculateRectangleArea($length, $width);
echo "矩形的面積：" . $rectangleArea . "\n";

// 定義一個(gè)圖形的抽象類
abstract class Shape {
    protected $name;
    
    public function __construct($name) {
        $this->name = $name;
    }
    
    abstract public function calculateArea();
    
    public function getName() {
        return $this->name;
    }
}
// 定義一個(gè)圓形類
class Circle extends Shape {
    private $radius;
    
    public function __construct($name, $radius) {
        parent::__construct($name);
        $this->radius = $radius;
    }
    
    public function calculateArea() {
        return 3.14 * $this->radius * $this->radius;
    }
}
// 定義一個(gè)矩形類
class Rectangle extends Shape {
    private $length;
    private $width;
    
    public function __construct($name, $length, $width) {
        parent::__construct($name);
        $this->length = $length;
        $this->width = $width;
    }
    
    public function calculateArea() {
        return $this->length * $this->width;
    }
}
// 創(chuàng)建一個(gè)圓形對(duì)象
$circle = new Circle("圓形", 5);
echo $circle->getName() . "的面積：" . $circle->calculateArea() . "\n";
// 創(chuàng)建一個(gè)矩形對(duì)象
$rectangle = new Rectangle("矩形", 4, 6);
echo $rectangle->getName() . "的面積：" . $rectangle->calculateArea() . "\n";