Interface Shape

Different classes can share a method shape by implementing the same interface.

interface_shape.php

<?php
interface Measurable
{
    public function measure(): int;
}

class Rectangle implements Measurable
{
    public function __construct(private int $width, private int $height)
    {
    }

    public function measure(): int
    {
        return $this->width * $this->height;
    }
}

$width = ;
$shape = new Rectangle($width, 3);
$area = $shape->measure();

echo "width=" . $width . "\n";
echo "area=" . $area . "\n";

<?php
interface Measurable
{
    public function measure(): int;
}

class Rectangle implements Measurable
{
    public function __construct(private int $width, private int $height)
    {
    }

    public function measure(): int
    {
        return $this->width * $this->height;
    }
}

$width = ;
$shape = new Rectangle($width, 3);
$area = $shape->measure();

echo "width=" . $width . "\n";
echo "area=" . $area . "\n";

<?php
interface Measurable
{
    public function measure(): int;
}

class Rectangle implements Measurable
{
    public function __construct(private int $width, private int $height)
    {
    }

    public function measure(): int
    {
        return $this->width * $this->height;
    }
}

$width = ;
$shape = new Rectangle($width, 3);
$area = $shape->measure();

echo "width=" . $width . "\n";
echo "area=" . $area . "\n";

shared shape The caller only needs the methods promised by the interface.