title: #define vs const in Objective-C
body: <p>I'm new to Objective-C, and I have a few questions regarding <code>const</code> and the preprocessing directive <code>#define</code>.</p>
  
  <p>First, I found that it's not possible to define the type of the constant using <code>#define</code>. Why is that?</p>
  
  <p>Second, are there any advantages to use one of them over the another one?</p>
  
  <p>Finally, which way is more efficient and/or more secure?</p>