title: How to check null class in C++
body: <p>How do I check if a class is null or not in C++? Suppose I have class <code>Line</code>:</p>
  
  <pre><code>Line line[1000];
  
  if (line[0] == NULL)
     cout &lt;&lt; "NULL";
  else
     cout &lt;&lt; "NOT NULL";
  </code></pre>
  
  <p>I get this error message:</p>
  
  <blockquote>
    <p>no match for 'operator=' in 'line[i] = 0'</p>
  </blockquote>