text: #include "template_base_class.h"
  template<typename T>
  class Derived : public Base<T>
  {
  public:
      using Base<T>::print_base;
      using Base<T>::data;
      Derived(T x);
      void print_derived();
  private:
  };
  
  template<typename T>
  Derived<T>::Derived(T x) : Base<T>::Base(x) {}
  
  template<typename T>
  void Derived<T>::print_derived()
  {
      print_base();
      std::cout << "data " << data << std::endl;
  }
  