Constructor Defaults

A constructor can provide defaults so object creation stays convenient.

constructor_defaults.php

<?php
class ShippingBox
{
    public function __construct(private int $weight = 1)
    {
    }

    public function cost(int $rate): int
    {
        return $this->weight * $rate;
    }
}

$rate = ;
$defaultCost = (new ShippingBox())->cost($rate);
$heavyCost = (new ShippingBox(3))->cost($rate);

echo "rate=" . $rate . "\n";
echo "defaultCost=" . $defaultCost . "\n";
echo "heavyCost=" . $heavyCost . "\n";

<?php
class ShippingBox
{
    public function __construct(private int $weight = 1)
    {
    }

    public function cost(int $rate): int
    {
        return $this->weight * $rate;
    }
}

$rate = ;
$defaultCost = (new ShippingBox())->cost($rate);
$heavyCost = (new ShippingBox(3))->cost($rate);

echo "rate=" . $rate . "\n";
echo "defaultCost=" . $defaultCost . "\n";
echo "heavyCost=" . $heavyCost . "\n";

<?php
class ShippingBox
{
    public function __construct(private int $weight = 1)
    {
    }

    public function cost(int $rate): int
    {
        return $this->weight * $rate;
    }
}

$rate = ;
$defaultCost = (new ShippingBox())->cost($rate);
$heavyCost = (new ShippingBox(3))->cost($rate);

echo "rate=" . $rate . "\n";
echo "defaultCost=" . $defaultCost . "\n";
echo "heavyCost=" . $heavyCost . "\n";

optional constructor input Default constructor values let a class support both explicit and ordinary setup.