title: C++ avoiding dynamic dispatch in derived classes with using keyword
body: <p>In the following example, will I be using dynamic dispatch to call the virtual functions?</p>
  
  <pre><code>struct Base{
      virtual double fn(){return 3.2;}
  };
  struct Deri1 : public Base{
      using Base::fn;
  }
  struct Deri2 : public Base{
      virtual double fn(){return 4.6;}
  }
  </code></pre>
  
  <p>The classes I'm implementing contain much more information, but there is some that I want to keep default for some derived classes but override in others, the fn() in above code is an example of this. Basically, I'm just using the base class to avoid rewritting fn() every time it's not overridden. Is this the right way?</p>
  
  <p>Thanks!</p>