Even Fibonacci numbers PHP Solve

2.php

<?php
/*
 * projecteuler.net
 * Even Fibonacci numbers PHP Solve
 */

$previous = 1;
$current = 2;

$sum_even = $current;
while ($current < 4000000) {
  
  $next = $current + $previous;
  if ($next % 2 == 0) {
    $sum_even += $next;
  }
  
  $previous = $current;
  $current = $next;
}

echo "$sum_even\n";