////myheader.h
#include <vector>

class interface {
public:
  virtual int& getA() = 0;
  virtual int& getB() = 0;
  virtual int& getC() = 0;
};

class interface_impl_Y : public interface {
  int *a, *b, *c;
public:
  interface_impl_Y(int *aa, int *bb, int *cc) {
    a = aa;
    b = bb;
    c = cc;
  };
  int& getA() {return *a;};
  int& getB() {return *b;};
  int& getC() {return *c;};
};

class interface_impl_X : public interface {
  int a = 0, b = 0, c = 0;
public:
  interface_impl_X(int aa, int bb, int cc) {
    a = aa;
    b = bb;
    c = cc;
  };
  interface_impl_X(interface_impl_Y &y) {
    a = y.getA();
    b = y.getB();
    c = y.getC();
  };
  int& getA() {return a;};
  int& getB() {return b;};
  int& getC() {return c;};
};

template<>
class std::vector<interface> {
public:
  vector<int> a, b, c;
  void push_back(interface &i) {
    a.push_back(i.getA());
    b.push_back(i.getB());
    c.push_back(i.getC());
  }
  interface& operator[](int i) {
    return *(new interface_impl_Y(&a[i], &b[i], &c[i]));
  }
};

////main.cpp
#include <vector>
#include "myheader.h"

using namespace std;

int main() {
  auto insert = interface_impl_X(1, 2, 3);
  vector<interface_impl_X> AoS;
  AoS.push_back(insert);

  vector<interface> SoA;
  SoA.push_back(insert);
}