PHP Master | Understanding Recursion

# Created by https://www.gitignore.io/api/laravel

### Laravel ###
vendor/
node_modules/
npm-debug.log

# Laravel 4 specific
bootstrap/compiled.php
app/storage/

# Laravel 5 & Lumen specific
public/storage
public/hot
storage/*.key
.env.*.php
.env.php
.env
Homestead.yaml
Homestead.json

# Rocketeer PHP task runner and deployment package. https://github.com/rocketeers/rocketeer
.rocketeer/

Start-Process powershell.exe -verb runAs -ArgumentList '-NoExit', '-Command', 'cd D:\folder'

composer self-update --1

<?php
function factorial ($number, $factorial = 1) {
    if ($number < 0) {
        throw new InvalidArgumentException('Number cannot be less than zero (0)');
    }
    if ($number == 0) {
        return $factorial;
    }
    else {
        return factorial($number - 1, $factorial * $number);
    }
}