pass-to-base.cpp   [plain text]

#include <stdio.h>
#include <memory>

class Extra
{
public:
  Extra (int in_one, int in_two) : m_extra_one(in_one), m_extra_two(in_two) {}

private:
  int m_extra_one;
  int m_extra_two;
};

class A
{
public:
  A(int value) : m_a_value (value) {}
  A(int value, A* client_A) : m_a_value (value), m_client_A (client_A) {}

  virtual ~A() {}

  virtual void
  doSomething (A &anotherA)
  {
    printf ("In A %p doing something with %d.\n", this, m_a_value);
    int tmp_value = anotherA.Value();
    printf ("Also have another A at %p: %d.\n", &anotherA, tmp_value); // Break here in doSomething.
  }

  int 
  Value()
  {
    return m_a_value;
  }

private:
  int m_a_value;
  std::auto_ptr<A> m_client_A;
};

class B : public Extra, public virtual A
{
public:
  B (int b_value, int a_value) : Extra(b_value, a_value), A(a_value), m_b_value(b_value) {}
  B (int b_value, int a_value, A *client_A) : Extra(b_value, a_value), A(a_value, client_A), m_b_value(b_value) {}

  virtual ~B () {}

private:
  int m_b_value;
};

static A* my_global_A_ptr;

int
main (int argc, char **argv)
{
  my_global_A_ptr = new B (100, 200);
  B myB (10, 20, my_global_A_ptr);
  B *second_fake_A_ptr = new B (150, 250);
  B otherB (300, 400, second_fake_A_ptr);

  myB.doSomething(otherB); // Break here and get real addresses of myB and otherB.

  A reallyA (500);
  myB.doSomething (reallyA);  // Break here and get real address of reallyA.

  return 0;
}