title: cpp <chrono>- member type defenition
body: <p>I am learning cpp. I thought that memeber type are functions/variable which belong to a type.
  For exanple in the following</p>
  
  <pre><code>class person
  {
  public:
      string name;
      int age;
  };
  </code></pre>
  
  <p>name and age are member type (in this case member class) of the person class.</p>
  
  <p>Recently I started to read about <code>&lt;chrono&gt;</code> library, and thaen I started to confused.
  There is  for example <code>class system_clock</code> which has <code>time_point</code> member type. But on the other hand there is also class <code>time_point</code> which has Clock member type (e.g class system_clock).</p>
  
  <p>How can a class contains sompe type as a member type and also be a member type of its own member type.</p>
  
  <p>I hope that I succeeded to explain my confusion.</p>