1. Define a class B1 with a virtual function vf() and a non-virtual function f(). Define both of these functions within class B1. Implement each function to output its name (e.g., B1::vf()). Make the functions public. Make a B1 object and call each function.

2. Derive a class D1 from B1 and override vf(). Make a D1 object and call vf() and f() for it.

3. Define a reference to B1 (a B1&) and initialize that to the D1 object you just defined. Call vf() and f() for that reference.