vtable question: why its own method is called rather than the parent's one?

[haiyeong]

class B derives from class A,
A has two virtual methods: f1( ) and f2( ). In A::f1( ), it call f2( ).
B override both virtual methods. In B::f1( ), it call A::f1( ). The question is: why B::f2( ) is called rather than A::f2( ).

Thanks!

#include <stdio.h>

class A
{
    public: virtual void f1()
    {
        f2();
    }

    public: virtual void f2()
    {
        printf("A.f2()\n");
    }
};

class B : A
{
    public: virtual  void f1()
    {
        A::f1();
    }
    public: virtual void f2()
    {
        printf("B.f2()\n");
    }
};

int main(int argc, char** argv)
{
    B * b = new B();
    b->f1();
    delete b;
}

The output is:
>> B.f2()