Default Arguments

Default argument values are used when a caller omits an optional parameter.

default_arguments.php

<?php
function totalWithFee(int $subtotal, int $fee = 4): int {
    return $subtotal + $fee;
}

$subtotal = ;
$standard = totalWithFee($subtotal);
$express = totalWithFee($subtotal, 10);

echo "subtotal=" . $subtotal . "\n";
echo "standard=" . $standard . "\n";
echo "express=" . $express . "\n";

<?php
function totalWithFee(int $subtotal, int $fee = 4): int {
    return $subtotal + $fee;
}

$subtotal = ;
$standard = totalWithFee($subtotal);
$express = totalWithFee($subtotal, 10);

echo "subtotal=" . $subtotal . "\n";
echo "standard=" . $standard . "\n";
echo "express=" . $express . "\n";

<?php
function totalWithFee(int $subtotal, int $fee = 4): int {
    return $subtotal + $fee;
}

$subtotal = ;
$standard = totalWithFee($subtotal);
$express = totalWithFee($subtotal, 10);

echo "subtotal=" . $subtotal . "\n";
echo "standard=" . $standard . "\n";
echo "express=" . $express . "\n";

default argument A default argument gives a parameter a fallback value.