what does ? sign in this statement?
<blockquote>
  <p><strong>Possible Duplicates:</strong><br>
  <a href="http://stackoverflow.com/questions/889373/quick-php-syntax-question">quick php syntax question</a><br>
  <a href="http://stackoverflow.com/questions/3737139/reference-what-does-this-symbol-mean-in-php">Reference - What does this symbol mean in PHP?</a>  </p>
</blockquote>



<p>$row_color = ($row_count % 2) ? $color1 : $color2;</p>
