// CopyAndAssignment.cpp

#include <string>
#include <vector>
#include <iostream>

class A 
{ 
public:
  A(const std::string& s) : _s(s) {}
  std::string& getString() { return _s; }
private:
  std::string _s; 
};

class B : public A 
{
public:
  B();
  B(const B& b);
  B& operator=(const B& b);
  int& operator[](int i);
  B& push_back(int i);
  void show();
private:
  std::vector<int>* pV;
};

B::B() : A("default string")
{
  pV = new std::vector<int>();
}

B::B(const B& b) : A(b)
{
  pV = new std::vector<int>(*(b.pV));

// This works too
//   pV = new std::vector<int>();
//   for(unsigned int i=0; i<b.pV->size(); ++i)
//     pV->push_back((*b.pV)[i]);
};

B& B::operator =(const B& b)
{
  if(this != &b)
  {
    (A&)*this = b;
    pV->clear();
    *pV = *b.pV;  // vector assignment

  // could also do this:
  //  (A&)*this = b;
  //  delete pV;
  //  pV = new std::vector<int>(*(b.pV));  // vector copy
  //
  // this works too for last statement
  //   pV = new std::vector<int>();
  //   for(unsigned int i=0; i<b.pV->size(); ++i)
  //     pV->push_back((*b.pV)[i]);
  //
  }
  return *this;
}

int& B::operator[](int i)
{
  return ((*pV)[i]);
}

B& B::push_back(int i)
{
  pV->push_back(i);
  return *this;
}

void B::show()
{
  std::cout << "\n  " << getString().c_str() << " : ";
  for(unsigned int i=0; i<pV->size(); ++i)
    std::cout << (*pV)[i] << " ";
  std::cout << "\n\n";
}

void main()
{
  B b;
  b.push_back(0).push_back(1).push_back(2).push_back(3);
  b.getString() = "original vector ";
  b.show(); 
  B c = b;
  c.getString() = "after copy      ";
  c.show();
  B d;
  d = b;
  d.getString() = "after assignment";
  d.show();
}