title: Is there a NULL equivalent for pairs in C++?
body: <p>What would I want to use instead of NULL if I have an unassigned pair in C++?</p>
  
  <p>As an example, suppose I have (pseudo)code like the following:</p>
  
  <pre><code>pair&lt;int,int&gt; bestPair; //Global variable
  
  updateBestPair(vector&lt;int&gt; a, vector&lt;int&gt; b) {
  
      bestPair = NULL;
  
      for (/* loop through a and b */) {
          if (/* pair(a,b) is better than bestPair and better than some baseline */)
              bestPair = make_pair(a,b);
      }
  
      if (bestPair != NULL) //Found an acceptable best pair
          function(bestPair);
      else
          cout&lt;&lt;"No acceptable pairs found"&lt;&lt;endl;
  }
  </code></pre>