C++ :: OOP Compare Member Function

I have an assignment in my OOP c++ class and I had to create a class called date and one of the member functions is a compare function that compares two dates that are taken in. It is suppose to be something like this:

Date d1(12,25,2003);// Dec 25, 2003
Date d2(5,18,2002);// May 18, 2002

d1.Compare(d2);// returns 1 (since d2 comes first)
d2.Compare(d1);// returns -1 (calling object is d2, comes first)

Then if d1 and d2 are equal then it returns 0.

This is what he gave us to start with the function:

int Date::Compare(const Date& d) {
}