No member named 'empty' in 'Patient'
for (size_t k{0}; k < 12; k++){
for (size_t l{0}; l < 5; l++){
if (weeklyAppointments[k][l]->empty() != false){
cout << weeklyAppointments[k][l]->get_patient_name() << "\t\t\t\t";
}
else{
cout << *(*(weeklyAppointments+(k))+(l))
}
}