Why does a virtual function get hidden?

Question

I have the following classes:

class A {
public:
    virtual void f() {}
};


class B : public A{
public:
    void f(int x) {}
};

If I say

Answer 1

Class B does not derive from A so no function F() exists. You probably meant:

class A {
public:
    virtual void f() {}
};


class B : public A {
public:
    void f(int x) {}
};

Edit: I missed the actual function hiding. See Steve Jessop answer for more thorough explanation.