14. Disabling copy example

• Since our reasons might not be immediately obvious to the user,
  each private member needs a short sentence of explaination:

  
      class Example {
      public:
          // constructor
          explicit Example();
  
          // destructor
          ~Example();
  
      private:
          // Copy constructor
          // is declared private so interface cannot use it;
          // not defined so implementation cannot use it:
          explicit Example( Example const& original );
  
          // Assignment operator
          // is declared private so interface cannot use it;
          // not defined so implementation cannot use it:
          Example& operator=( Example const& original );
  
      };//class Example