#include <iostream>

using namespace std;

struct Vector
{ int * v;
  int size;

  Vector()   // no return type, same name as object = CONSTRUCTOR
  { size = 0;
    v = new int[0]; }

  // Functions inside an object are called METHODS
  void setsize(int sz)
  { if (sz < 0)
    { cout << "Can't create an array of size " << sz << "\n";
      exit(1); }
    int * temp = new int[sz];
    int amt = min(size, sz);
    for (int i = 0; i < amt; i += 1)
      temp[i] = v[i];
    v = temp;
    size = sz; }

  int getsize()
  { return size; }

  int & access(int pos)
  { if (pos < 0 || pos >= size)
    { cout << "Index to array is out of bounds\n";
      exit(1); }
    return v[pos]; }
};

int main()
{ Vector R;
  int n;
  cout << "How big would you like the array to be? ";
  cin >> n;
  R.setsize(n);

  for (int i = 0; i < R.getsize(); i += 1)
    R.access(i) = 1000 + i;
  /* pretend to use the array here */

  // I discover that the array needs to be even bigger, let's say N*2
  R.setsize(n*2);
  // fill in the rest of the array now
  for (int i = n; i < R.getsize(); i += 1)
    R.access(i) = 1000 + i;

  cout << "The array contains:\n";
  for (int i = 0; i < R.getsize(); i += 1)
    cout << "  R[" << i << "] = " << R.access(i) << "\n";
}