Avoiding adding a default method to the subclass

WithDefault.cpp

class SuperClass {

  void defaultDummyMethod() {
    // This is the no-op dummy method that will be overriden in some child class
    doNothing();
  }
  
  void actualMethod() {
    // This has lots of gnarly code, plus a call to the dummy method, 
    // even though this class doesn't need to call the dummy method.
    // Lots of gnarly code
    defaultDummyMethod();
  }
  
}

class SubClass : public superClass {
  void defaultDummyMethod() {
    // This overrides the dummy method
    doTheExtraThing();
  }
}

WithoutDefault.cpp

class SuperClass {
  public void actualMethod() {
    // This is the publicly exposed method
    // A client would call this method, that just delegates to another method
    gnarlyCode();
  }
  
  protected void gnarlyCode() {
  // This is only visible to this class and its children
  // Lots of gnarly code
  }
}

class SubClass : public superClass {
  public void actualMethod() {
    // This overrides the parent method, also delegates functionality 
    // to the inherited gnarlyCode() and adds a call to the stuff only
    // this subclass needs to do
    gnarlyCode();
    doTheExtraThing();
  }
  
  private void doTheExtraThing() {
    // The stuff that only this subclass needs to do.
    doStuff();
  }
}