title: Should I move the class to the end of the file by using the forward declaration?
body: <p>In one file, I can write the following two codes, which one is better for other maintainers?</p>
  
  <p>First (top-down feeling):</p>
  
  <pre><code>Class B;
  Class A {
    B *b;
  };
  Class B {
  };
  </code></pre>
  
  <p>Second (bottom-up feeling):</p>
  
  <pre><code>Class B {
  };
  Class A {
    B *b;
  };
  </code></pre>