title: difference between ARC and MRC
body: <p>I am confused with Apple material.  </p>
  
  <p>In 3 ways we manage the memory, they are :  </p>
  
  <ol>
  <li>automatic referance counting.</li>
  <li>manual   reference counting.</li>
  <li>garbage colletion.  </li>
  </ol>
  
  <p>My doubt is what is the difference between automatic reference counting and manual referance counting.</p>
  
  <p>Can someone explain me ?</p>