/////////////////////////////////////////////////////////////////////
// MT3Q8.cpp

#include<iostream>

//////////////////////////////////////////
// class that shares its reference
// could have state lifetime problems

class B1
{
public:
  B1(std::string& str) : s(str) {}
  B1(const B1& b);
  B1& operator=(const B1& b);
  void say() { std::cout << "\n  " << s.c_str(); }
private:
  std::string& s;
};

B1::B1(const B1& b) : s(b.s) {}

B1& B1::operator =(const B1 &b)
{
  // does nothing, since the reference is shared
  return *this;
}

////////////////////////////////////////////
// class that shares a pointer to string
// also could have lifetime problems

class B2
{
public:
  B2(std::string& str) : pS(&str) {}
  B2(const B2& b);
  B2& operator=(const B2& b);
  void say() { std::cout << "\n  " << pS->c_str(); }
private:
  std::string* pS;
};

B2::B2(const B2& b) : pS(b.pS) {}

B2& B2::operator=(const B2& b)
{
  if(this == &b) return *this;
  if(pS != b.pS)
  {
  //  delete pS;  do this if you know pS points to heap
    pS = b.pS;
  }
  return *this;
}

void main()
{
  std::string str = "I'm a B1 object";
  B1 b1a(str);
  b1a.say();
  B1 b1b = b1a;
  b1b.say();
  std::cout << "\n\n";

  B1 b1c(str);
  b1c.say();
  b1c = b1a;
  b1c.say();
  std::cout << "\n\n";

  str = "I'm a B2 object";
  B2 b2a(str);
  b2a.say();
  B2 b2b = b2a;
  b2b.say();
  std::cout << "\n\n";

  std::string str2 = "I will be assigned";
  B2 b2c(str2);
  b2c.say();
  b2c = b2a;
  b2c.say();
  std::cout << "\n\n";
}