/*
 * initializing-virtual-bases.cc
 *
 * This example illustrates how construction of subobjects in a class 
 * lattice with virtual base classes is done. Trace print-outs from
 * constructors and destructors shows construction and destruction
 * order.
 */
#include <iostream>
using namespace std;

struct Member_1 {
   Member_1(int i) : i_(i) {
      cout << "  Member_1     subobject initialized: i = " << i << endl;
   }

   ~Member_1() { cout << "  Member_1     subobject destroyed" << endl; }

   int i_;
};

struct Member_2 {
   Member_2(int i) : i_(i) {
      cout << "  Member_2     subobject initialized: i = " << i << endl;
   }

   ~Member_2() { cout << "  Member_2     subobject destroyed" << endl; }

   int i_;
};

struct Member_3 {
   Member_3(int i) : i_(i) {
      cout << "  Member_3     subobject initialized: i = " << i << endl;
   }

   ~Member_3() { cout << "  Member_3     subobject destroyed" << endl; }

   int i_;
};

struct Base_1 {
   Base_1(int m1) : m1_(m1) {
      cout << "  Base_1       subobject initialized: m = " << m1 << endl;
   }

   ~Base_1() { cout << "  Base_1       subobject destroyed" << endl; }

   int get_value() const { return m1_.i_; }

   Member_1 m1_;
};

struct Base_2 {
   Base_2(int m2) : m2_(m2) {
      cout << "  Base_2       subobject initialized: m = " << m2 << endl;
   }

   ~Base_2() { cout << "  Base_2       subobject destroyed" << endl; }

   int get_value() const { return m2_.i_; }

   Member_2 m2_;
};

struct Base_3 {
   Base_3(int m3) : m3_(m3) {
      cout << "  Base_3       subobject initialized: m = " << m3 << endl;
   }

   ~Base_3() { cout << "  Base_3       subobject destroyed" << endl; }

   int get_value() const { return m3_.i_; }

   Member_3 m3_;
};

struct Virtual_1 : public Base_2, public Base_3 {
   Virtual_1(int b2, int b3, int m1)
      : Base_2(b2), Base_3(b3), m1_(m1) 
   {
      cout << "  Virtual_1    subobject initialized: m = " << m1 << endl;
   }

   ~Virtual_1() { cout << "  Virtual_1    subobject destroyed" << endl; }

   Member_1 m1_;
};

struct Virtual_2 : public Base_1, public Base_3 {
   Virtual_2(int b1, int b3) 
      : Base_1(b1), Base_3(b3)
   {
      cout << "  Virtual_2    subobject initialized: s = " << s2_.i_ << endl;
   }

   ~Virtual_2() { cout << "  Virtual_2    subobject destroyed" << endl; }

   static Member_2 s2_;
};

Member_2 Virtual_2::s2_(0);

// The initializer for Virtual_1 is ignored when initializing an object of type subclass
// to Derived_1.
struct Derived_1 : public Base_1, virtual public Virtual_1  {
   Derived_1(int v11, int v12, int v13, int b1)
      : Virtual_1(v11, v12, v13), Base_1(b1)
   {
      cout << "  Derived_1    subobject initialized" << endl;
   }

   ~Derived_1() { cout << "  Derived_1    subobject destroyed" << endl; }
};

// The initializer for Virtual_2 is ignored when initializing an object of type subclass
// to Derived_2.
struct Derived_2 : virtual public Virtual_1 {
   Derived_2(int v11, int v12, int v13, int m2) 
      : Virtual_1(v11, v12, v13), m2_(m2)
   {
      cout << "  Derived_2    subobject initialized: m2_ = " << m2 << endl;
   }

   ~Derived_2() { cout << "  Derived_2    subobject destroyed" << endl; }

   Member_2 m2_;
};

// The initializers for Virtual_1 and Virtual_2 are ignored when initializing an object
//  of type subclass to Derived_3.
struct Derived_3 : public Derived_1, public Derived_2, virtual public Virtual_2 {
   Derived_3(int v11, int v12, int v13, int v21, int v22, int m1, int m2, int m3) 
      :  Virtual_1(v11, v12, v13),
	 Virtual_2(v21, v22),     
	 Derived_1(v11, v12, v13, m1), 
	 Derived_2(v11, v12, v13, m2), m3_(m3)
   {
      cout << "  Derived_3    subobject initialized: m = " << m3_.i_ << endl;
   }

   ~Derived_3() { cout << "  Derived_3    subobject destroyed" << endl; }

   Member_3 m3_;
};

// The initializers for Virtual_1 and Virtual_2 are used when initializing an object of
// type Most_Derived (such as x below). Initializers for Virtual_1 and Virtual_2 in the
// base classes to Most_Derived are ignored.
struct Most_Derived : public Derived_3 {
   Most_Derived() 
      : Virtual_1(11, 12, 13),
	Virtual_2(21, 22),    
   	Derived_3(311, 312, 313, 321, 322, 301, 302, 303),
	m2_(2), m3_(3)
   {
      cout << "  Most_Derived object initialized" << endl;
   }

   ~Most_Derived() { cout << "  Most_Derived object destroyed" << endl; }

   using Base_2::get_value;

   static Member_1 s1_;
   Member_2        m2_;
   Member_3        m3_;
};

Member_1 Most_Derived::s1_(0);

int main()
{
   cout << "\nTraces from initialization if the object x (Most_Derived):" << endl;
   Most_Derived x;

   cout << "\nx.get_value() = " << x.get_value() << endl;

   cout << "\nTraces from destruction of x and static objects (last):" << endl;
   return 0;
}