title: index , pointer , iterator , which is better ? when it comes to vectors
body: <p>hi i'm doing a program that needs high performance of handling vector elements </p>
  
  <pre><code>vector&lt;Class_A&gt; object ;
  </code></pre>
  
  <p>1- which one is fastest to access the elements 
  2- which is more code simpler and not complex to deal with </p>
  
  <p>index ? iterator ? pointer ?</p>