.h file
friend ostream& operator<<(ostream&, ListOfEmployee);

.cpp file
ostream& operator<<(ostream& os, ListOfEmployee list) {
	EmployeeNode* temp = list.getHead();
	if (temp == NULL) {
		os << "List is empty" << endl;
		return os;
	}
	while (temp != NULL) {
		Employee e = temp->getEmp();
		os << "Name: " << e.getName()
			<< "\nSalary: " << e.getSalary() << endl << endl;;
		temp = temp->getNext();
	}

	return os;
}