title: Objective c : can't understand how a #define macro is expanded
body: <p>Hello,</p>
  
  <pre><code>#define A 1+5
  int a = A/A;
  NSLog(@"value a %d",a);
  </code></pre>
  
  <p>it shows me the result is  11</p>
  
  <p>Please can you explain me how it works? 
  I want to understand the steps that the compiler does to show this result.
  thank you in advance.</p>