title: Pointers to a class within itself in C++
body: <p>I am analyzing some codes in c++ and I came across this configuration.</p>
  
  <pre><code>class jack {
    //rest of the class body here
    public:
      jack *a;
  };
  </code></pre>
  
  <p>What is the theory of using a pointer in that configuration?</p>