// virtinh.cc       demonstrate multiple inheritance with 'virtual'
//                  design requirement needs only one copy of A in D
//                  compare this to multinh.cc

class A               // base class for B and C
{                     // indirect class for D
  public:
    int p, q;
};

class B : virtual public A    // single inheritance, virtual
{
  public:
    int q, r;           // now have A::p  A::q  B::q  B::r
};

class C : virtual public A    // another single inheritance, virtual
{
  public:
    int q, s;           // now have A::p  A::q  C::q  C::s
};

class D : public B, public C  // multiple inheritance, only one A
{                             // class inherited because B, C virtuals
  public:
    int q, t;           // now have A::p  A::q  B::q  B::r
};                      //          C::q  C::s  D::q   D::t

#include <iostream>
using namespace std;

int main()
{
  D stuff;             // eight (8) integers

  stuff.p = 1;         // the local p in A
  stuff.A::q = 2;      // the local q in A   note four (4) q's
  stuff.B::q = 3;      // the local q in B
  stuff.C::q = 4;      // the local q in C
  stuff.q = 5;         // the local q in D
  stuff.r = 6;         // from B unambiguous
  stuff.s = 7;         // from C unambiguous
  stuff.t = 8;         // from D unambiguous
  cout << stuff.p    << stuff.A::q << stuff.B::q << stuff.C::q
       << stuff.D::q << stuff.r    << stuff.s    << stuff.t
       << '\n';
  return 0;        // prints   12345678 to show eight variables stored
}