title: NSNotFound comparison not working
body: <p>Simple one.</p>
  
  <p>I'm using indexOfObject to check if a value is already in an array.</p>
  
  <p>If the value isn't in the array indexOfObject returns the constant NSNotFound.</p>
  
  <p>Why does comparison with > 100000 work: </p>
  
  <pre><code>NSInteger indexOfCell = [_selectedCellIndices indexOfObject:cellIndex];
  
  if(indexOfCell &gt; 1000000)
  </code></pre>
  
  <p>but equality with NSNotFound fail:</p>
  
  <pre><code>NSInteger indexOfCell = [_selectedCellIndices indexOfObject:cellIndex];
  
  if(indexOfCell == NSNotFound)
  </code></pre>