Sorting Vector(Bubble sort) c++

I have class Date, functions bubbleSort, isAfter and printVector. So my task is: Use the function bubbleSort to sort vector type objects Date(using function isAfter which compares dates). I've done something but it doesn't works, so can anyone help me with this? Function bubble sort(doesn't works with "Date", works fine with integers ,strings...). Here is my code:

//isAfter
template<>
bool isAfter(const Date &first, const Date &second) {
    if (first.getYear() == second.getYear()) {
        if (first.getMonth() == second.getMonth()) {
            if (first.getDay() == second.getDay()) {
                cout << first.toString() << " is equal to " << second.toString() << endl;
                return false;
            } else if (first.getDay() > second.getDay()) {
                cout << " " << first.toString() << " is after " << " " << second.toString() << endl;
                return true;
            } else if (first.getDay() < second.getDay()) {
                cout << " " << second.toString() << " is after " << " " << first.toString() << endl;
                return true;
            }
        } else if (first.getMonth() > second.getMonth()) {
            cout << " " << first.toString() << " is after " << " " << second.toString() << endl;
            return true;
        } else if (first.getMonth() < second.getMonth()) {
            cout << " " << second.toString() << " is after " << " " << first.toString() << endl;
            return true;
        }
    } else if (first.getYear() > second.getYear()) {
        cout << " " << first.toString() << " is after " << " " << second.toString() << endl;
        return true;
    } else if (first.getYear() < second.getYear()) {
        cout << " " << second.toString() << " is after " << " " << first.toString() << endl;
        return true;
    }
    return false;
}

//bubbleSort
template<typename T>
void bubbleSort(vector<T> &vec) {
    bool swapp= true;
    while (swapp) {
        swapp= false;
        for (unsigned int i = 0; i < vec.size()- 1; i++) {
            if (vec[i] > vec[i + 1]) {
                swap(vec[i], vec[i + 1]);
                swapp = true;
            }

        }
    }
}

so how can i add isAfter in bubbleSort to work fine with "Date" objects?