title: check if a std::vector contains a certain object?
body: <p>Is there something in <code>&lt;algorithm&gt;</code> which allows  you to check if a std:: container contains something? Or, a way to make one, for example:</p>
  
  <pre><code>if(a.x == b.x &amp;&amp; a.y == b.y)
  return true;
  
  return false;
  </code></pre>
  
  <p>Can this only be done with <code>std::map</code> since it uses keys?</p>
  
  <p>Thanks</p>