Consider the following requirements specification for a computerized appointments system for a doctors' surgery.

"The system will be primarily operated by the doctors' receptionists. They will make appointments for patients who contact the surgery. To make an appointment the receptionist gets the patient's name, checks that the patient is registered and gets the next available appointment slot. Providing this slot is acceptable to the patient the appointment is confirmed and the diary updated. The system should enable receptionists to cancel appointments either in response to patients' or doctors' requests. If a patient cancels a confirmed appointment within 24 hours, he has to pay 50 Rs. cancellation charges; patients who fail to turn up for an appointment must pay 100 Rs. charges. The system must prepare invoices for customers who have to pay charges. As the system is only to be used by receptionists or doctors it should have user friendly interface and an appropriate login procedure that will only allow authorized users to enter the system."


a) Identify all non-functional requirements. 

b) Identify all the actors and use cases and draw the corresponding use case diagram.

c) Elaborate Make Appointment use case. Clearly identify the pre-condition, post- condition, normal course and the alternative courses.