Why doesn't the compiler complain in the definition of the Derived class constructor?

Question

Notice that the Derived class constructor has ii as its first argument, but the argument passed to Base was made equal to i on purpose.

class Base
{
    protected:
    int i;

    public:
    Base(int i) : i(i) {}
};

class Derived : public Base
{
    private:
    int k;

    public:
    Derived(int ii, int k) : Base(i), k(k) {}  // Why not C2065: 'i' undeclared identifier
};

int main()
{

}

Answer 1

Because i is a member variable inherited from Base, so it is defined. You can freely access member variables in initialiser lists, but what you're doing is accessing a variable before it's initialised, which is, I believe, Undefined Behaviour.