#include <iostream>
 
struct A
{
    A(int a) : a(a) { std::cout << __PRETTY_FUNCTION__ << std::endl; }
    int a;
};
 
struct B : virtual public A
{
    B() : A('b') { std::cout << __PRETTY_FUNCTION__ << std::endl; }
};
 
struct C : virtual public A
{
    C() : A('c') { std::cout << __PRETTY_FUNCTION__ << std::endl; }
};
 
struct D : public B, public C
{
    // Note: virtual base class initialied *here*
    D() : A('d') { std::cout << __PRETTY_FUNCTION__ << std::endl; }
};
 
int main()
{
    B b;
    C c;
    D d;
    std::cout << b.a << ',' << c.a << ',' << d.a << std::endl;
    return 0;
}

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