title: C macro: #if check for equality
body: <p>Is there a way to do check for numerical equality in macros?</p>
  
  <p>I want to do something like</p>
  
  <pre><code>#define choice 3
  
  #if choice == 3
    ....
  #endif
  
  #if choice == 4
   ...
  #endif
  </code></pre>
  
  <p>Does C macros have support for things like this?</p>