// revised_vector.h: based on simple_vector, but with const
// based on Stroustrup, A Tour of C++ (2014), p. 37

#ifndef _MEGAVECTOR_H
#define _MEGAVECTOR_H

#include <stdexcept>

class AbstractContainer {
public:
  virtual ~AbstractContainer() { }
  virtual int size() const = 0;
  virtual double& operator[](int index) = 0;
  virtual const double& operator[](int index) const = 0;
};  

class MegaVector : public AbstractContainer {
public:
  static constexpr int SIZE = 1000000;

  MegaVector() {
    for(int i = 0; i < SIZE; ++i)
      elements[i] = 0.0;
  }
   
  int size() const override { return SIZE; }

  double& operator[](int index) override {
    if ( index < 0 || index >= SIZE )
      throw std::out_of_range("Illegal index into vector.");
    return elements[index];
  }

  const double& operator[](int index) const override {
    if ( index < 0 || index >= SIZE )
      throw std::out_of_range("Illegal index into vector.");
    return elements[index];
  }

private:
  double elements[SIZE];
};

#endif