Symfony console

composer.json

{
    "require": {
        "symfony/console": "~2.6"
    },
    "autoload": {
        "psr-4": {"" : "src"}
    }
}

console

#!/usr/bin/env php
<?php

set_time_limit(0);

require_once __DIR__ . '/../vendor/autoload.php';

use Symfony\Component\Console\Application;
use HunterBundle\Command\FibonacciCommand;

$app = new Application();

$app->add(new FibonacciCommand());

$app->run();

FibonacciCommand.php

<?php

namespace HunterBundle\Command;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Formatter\OutputFormatterStyle;

class FibonacciCommand extends Command {

    protected function configure()
    {
        $start = 0;
        $stop = 100;

        $this->setName("hunter:fibonacci")
             ->setDescription("Display the fibonacci numbers between 2 given numbers")
             ->setDefinition(array(
                      new InputOption('start', 's', InputOption::VALUE_OPTIONAL, 'Start number of the range of Fibonacci number', $start),
                      new InputOption('stop', 'e', InputOption::VALUE_OPTIONAL, 'stop number of the range of Fibonacci number', $stop)
                ))
             ->setHelp(<<<EOT
Display the fibonacci numbers between a range of numbers given as parameters

Usage:

<info>php console.php hunter:fibonacci 2 18 <env></info>

You can also specify just a number and by default the start number will be 0
<info>php console.php hunter:fibonacci 18 <env></info>

If you don't specify a start and a stop number it will set by default [0,100]
<info>php console.php hunter:fibonacci<env></info>
EOT
);
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {

        $header_style = new OutputFormatterStyle('white', 'green', array('bold'));
        $output->getFormatter()->setStyle('header', $header_style);

        $start = intval($input->getOption('start'));
        $stop  = intval($input->getOption('stop'));

        if ( ($start >= $stop) || ($start < 0) ) {
           throw new \InvalidArgumentException('Stop number should be greater than start number');
        }

        $output->writeln('<header>Fibonacci numbers between '.$start.' - '.$stop.'</header>');

        $xnM2 = 0; // set x(n-2)
        $xnM1 = 1;  // set x(n-1)
        $xn = 0; // set x(n)
        $totalFiboNr = 0;
        while ($xnM2 <= $stop)
        {
            if($xnM2 >= $start)  {
                $output->writeln('<header>'.$xnM2.'</header>');
                $totalFiboNr++;
            }
            $xn = $xnM1 + $xnM2;
            $xnM2 = $xnM1;
            $xnM1 = $xn;

        }
        $output->writeln('<header>Total of Fibonacci numbers found = '.$totalFiboNr.' </header>');
    }
}