Analyzing the concept of polymorphism in PHP

Polymorphism concepts and code examples in PHP

In object-oriented programming, polymorphism is an important concept. It allows different objects to respond differently to the same message. In PHP, polymorphism can be achieved through interfaces and inheritance. Next we will analyze the concept of polymorphism in PHP through specific code examples.

First, we create an interface Shape, which contains a calculateArea method:

interface Shape {
    public function calculateArea();
}

Next, we create two classes Circle and Square respectively implement the Shape interface:

class Circle implements Shape {
    private $radius;
    
    public function __construct($radius) {
        $this->radius = $radius;
    }
    
    public function calculateArea() {
        return round(pi() * pow($this->radius, 2), 2);
    }
}

class Square implements Shape {
    private $sideLength;
    
    public function __construct($sideLength) {
        $this->sideLength = $sideLength;
    }
    
    public function calculateArea() {
        return pow($this->sideLength, 2);
    }
}

Next, we create a function getShapeArea, which accepts implementation Take the object of the Shape interface as a parameter and call its calculateArea method to calculate the area:

function getShapeArea(Shape $shape) {
    return $shape->calculateArea();
}

Now, we can create Circle and Square objects and call the getShapeArea function to calculate their areas:

$circle = new Circle(5);
$square = new Square(4);

echo "圆的面积：" . getShapeArea($circle) . "；"; // 输出：圆的面积：78.54；
echo "正方形的面积：" . getShapeArea($square) . "。"; // 输出：正方形的面积：16。

In the code example above, Circle and Square# The ## classes respectively implement the Shape interface and cover the calculateArea method to calculate the area based on the specific shape. By calling the getShapeArea function and passing in different objects, we achieve polymorphism based on different object instances.

In summary, polymorphism in PHP is implemented through interfaces and inheritance, allowing different objects to respond differently to the same message, thus improving the scalability and flexibility of the code. With proper design and implementation, polymorphism can be fully exploited to simplify code structure and improve code reusability.

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