activity diagram for hospital management system PlantUML Code ?

can use this code with a PlantUML tool or editor to generate the visual activity diagram.

```plantuml
@startuml HospitalManagementSystemActivityDiagram

start

:User inputs patient details;
:Validate and register the patient;

if (Appointment Booking?) then (yes)
  :User selects a doctor and preferred date/time;
  :Check doctor's availability;
  :Confirm the appointment and update the doctor's schedule;
else (no)
  :Exit to main menu;
endif

if (Medical Test Request?) then (yes)
  :Doctor reviews the patient's condition;
  :Order specific medical tests for the patient;
  :Record the test request in the patient's medical history;
else (no)
  :Exit to main menu;
endif

if (Discharge Process?) then (yes)
  :Doctor reviews the patient's condition and treatment progress;
  :Determine if the patient can be discharged;
  :Update the patient's status to "Discharged";
else (no)
  :Exit to main menu;
endif

stop

@enduml
```

In the above PlantUML code, we have represented the main activities of the Hospital Management System using the activity diagram notation. The diagram starts with the `start` symbol and ends with the `stop` symbol. It includes decision points (represented by `if-then-else` constructs) where the user’s choices lead to different activities.

To visualize this activity diagram, you can use any PlantUML-compatible editor or online tool that supports PlantUML rendering. Copy and paste the code into the tool to generate the corresponding activity diagram. The resulting diagram will represent the flow of activities in the Hospital Management System.