title: PHP include class in other class
body: <p>I am learning OOP and very confuse to use classes for each other.</p>
  
  <p>I am having total 3 classes</p>
  
  <pre><code>//CMS System class
  class cont_output extends cont_stacks
  {
      //all methods to render the output
  }
  
  
  //CMS System class
  class process
  {
      //all process with system and db
  }
  
  
  // My own class to extends the system like plugin
  class template_functions
  {
      //here I am using all template functions
      //where some of used db query
  }
  </code></pre>
  
  <p>Now I want to use my own class template_functions withing both system classes. But very confused how to use it. Please help me to understand this.</p>
  
  <p><strong>EDIT:
  I am sorry champs I forgot to mention that my own class in different PHP file.</strong></p>