title: How do I implement no-op macro (or template) in C++?
body: <p>How do I implement no-op macro in C++?</p>
  
  <pre><code>#include &lt;iostream&gt;   
  
  #ifdef NOOP       
      #define conditional_noop(x) what goes here?   
  #else       
      #define conditional_noop(x) std::cout &lt;&lt; (x)   
  #endif   
  int main() {       
      conditional_noop(123);   
  }
  </code></pre>
  
  <p>I want this to do nothing when NOOP is defined and print "123", when NOOP is not defined.</p>