C>class A
C>{
C>public:
C>    A()
C>    {
C>        f();
C>    }
C>    virtual void f(int i = 10)
C>    {
C>        std::cout << i << '\n';
C>    }
C>};

C>class B: public A
C>{
C>public:
C>    B()
C>    {
C>        f();
C>    }
C>    virtual void f(int i = 25) override
C>    {
C>        std::cout << "B::f " << i << '\n';
C>    }
C>};

C>int main()
C>{
C>    B b;
C>    A& a = b;
C>    a.f();
C>}
C>