/////////////////////////////////////////////////////////////////////
// MT2Q10.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);
  void say() { std::cout << "\n  " << s.c_str(); }
private:
  std::string& s;
};

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

////////////////////////////////////////////
// class that does not share its reference
// but, then why hold a reference?

class B2
{
public:
  B2(std::string& str) : s(*new std::string(str)) {}
  B2(const B2& b);
  ~B2() { delete &s; }
  void say() { std::cout << "\n  " << s.c_str(); }
private:
  std::string& s;
};

B2::B2(const B2& b) : s(*new std::string(b.s)) {}

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