#include <iostream>
using namespace std;

class Matrix {
    int sizex;
    int sizey;
    double * data;
  public:
    int size_x() const {
      return sizex;
    }
    int size_y() const {
      return sizey;
    }
    double get(int i, int j) {
      return data[i*sizey + j];
    }
};

class ThoroidalMatrix : public Matrix {
    double get(int i, int j) {
      i = i % size_x();
      j = j % size_y();
      return Matrix::get(i, j);
    }
};

class Base {
 public:
  void foo() {
    cout << "Base::foo()" << endl;
  }
};

class Derived : public Base {
 public:
  void foo() {
    cout << "Derived::foo()" << endl;
  }
};

int main() {
  Derived d;

  d.foo();
}