anonymous_class.cpp

#include <iostream>

// https://stackoverflow.com/questions/23979785/can-unnamed-structures-inherit

class Data1 {
  private:
    int data = 5;

  public:
    int get_data() {
        return data;
    }

    void set_data(int data) {
        this->data = data;
    }
};

class Data2 {
  private:
    int data = 10;

  public:
    int getData() {
        return data;
    }

    void setData(int data) {
        this->data = data;
    }
};

template <typename T> class AbstractDataManipulator {
  private:
    virtual int get_data(T &data) = 0;
    virtual void set_data(T &data, int new_data) = 0;

  public:
    void manipulate(T &data) {
        int old_data = get_data(data);
        std::cout << "Data: " << old_data << std::endl;
        set_data(data, old_data + 1);
    }
};

class DataManipulator : public AbstractDataManipulator<Data1> {
  private:
    int get_data(Data1 &data) {
        return data.get_data();
    }
    void set_data(Data1 &data, int new_data) {
        data.set_data(new_data);
    }
};

int main(int argc, char *argv[]) {
    Data1 D1;
    DataManipulator DM1;
    DM1.manipulate(D1);
    DM1.manipulate(D1);

    Data2 D2;
    static class : public AbstractDataManipulator<Data2> {
      private:
        int get_data(Data2 &data) {
            return data.getData();
        }
        void set_data(Data2 &data, int new_data) {
            data.setData(new_data);
        }
    } DM2;
    DM2.manipulate(D2);
    DM2.manipulate(D2);
    return 0;
}