This exercise works in the context of the divide program from the slide about constant references.
Program the struct ldiv_t and the function div yourself, instead of using the definitions from the std namespace.
Run the program with your own versions of ldiv_t and div.
Experiment with returning a reference ldiv_t& from div. (See page 282-283 in The C++ Programming Language).
And similarly, experiment with returning a const reference const ldiv_t& from the div.