title: Avoiding Circular Dependencies of header files
body: <p>Do you have any good advice on how to avoid <strong>circular dependencies of header files</strong>, please?</p>
  
  <p>Of course, from the beginning, I try to design the project as transparent as possible. However, as more and more features and classes are added, and the project gets less transparent, circular dependencies start happening.</p>
  
  <p><strong>Are there any general, verified, and working rules?</strong> Thanks.</p>