title: difference between nil and NULL
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/557582/null-vs-nil-in-objective-c">NULL vs nil in Objective-C</a><br>
    <a href="https://stackoverflow.com/questions/4283690/objective-c-whats-the-difference-between-null-nil-and">Objective-C: What&#39;s the difference between NULL, nil and @&ldquo;&rdquo;?</a>  </p>
  </blockquote>
  
  
  
  <p>all I have a simple problem that my <strong>objective variable has NULL value</strong> in it. and it simply enter <strong>in the if condition</strong>. I have to check that if variable objective length is greater then zero and no null value then enter in condition.</p>
  
  <p>and <strong>When I use NULL or nil in comparison</strong>?</p>
  
  <p>THANKS</p>
  
  <p><img src="https://i.stack.imgur.com/zzA0L.png" alt="enter image description here"></p>