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Exercise 7 - Assignment 2 Preparation (Week 8)/ex7.txt

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+Q1. Main program function (loop explained in detail in Q3).
+
+- Input file name
+
+- try opening file, print error and exit if fails
+
+- read two integers i.e. no. of business class and tourist class servers (these serve as artificial limits on respective idle server queues)
+
+- read (float, integer, float) and initialise min-heap with this event
+
+- start simulation loop in which event at the top min-heap is processed (explained in part Q3.)
+
+- seek to the top of the file for second scenario simulation
+
+- read (float, integer, float) and initialize min-heap with this event
+
+- start simulation loop in which event at the top min-heap is processed (explained in part Q3.). This time, business servers can serve tourist customers if free and business customer queue is empty (explained in Part Q3.)
+
+
+
+Q2. Event can be either arrival of new customer or completion of serving a customer
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+
+
+Q3. Each event (element in min-heap) has event ID. If id == 0 than event type is new customer arrival, else event is completion of serving a customer by a server. Server type is identified by server id no. Business class servers are in range 1-20 and tourist class servers in range 21-40. [Alternatively, business class server are in the range 1 to no. of business customers and tourist servers are above business customer servers.]
+
+- simulation while loop
+    - if heap[0].id == 0 i.e. event type is customer arrival than:
+        - save heap[0] in current_customer variable
+        - read next customer arrival in heap[0]
+            - if next read is (0, 0, 0) i.e. no more customers than:
+                - swap heap[0] with heap[-1]
+                - reduce heap size by 1
+            - else:
+                - replace heap[0] with next arrival record
+            - shiftdown(heap[0])
+        - (current_customer variable) if any of it's class server free i.e its idle server queue is not empty than:
+            - assign customer to that server
+            - add it to the back of heap
+            - Set its event time current time + service time (when the server will be finished with current customer)
+            - extend heap size by 1
+            - shiftup(Heap[-1])
+        - else if no server free
+            - add customer to respective queue
+    - else if heap[0].id != 0 i.e. event type is a server finished with serving a customer
+        - if respective queue isEmpty() == true:
+            - replace heap[0] with queue.pop() (first customer in queue)
+            - shiftdown(heap[0])
+        - else if respective isEmpty() == false:
+            - free server and add it to respective idle servers queue
+            - swap heap[0] with heap[-1] and reduce heap size by 1
+            - shift down heap[0]
+    - if heap_size == 0:
+        - break loop
+
+For second of simulation, all will be same except when business customer server finishes serving and business customer queue is empty:
+- if tourist customer queue is not empty
+    - server that tourist customer
+
+And:
+- if arrival is tourist customer:
+    - if no idle tourist server and tourist queue is empty:
+        - if any idle business server:
+            - assign customer to business server
+