159.341_Assignment_2/logic.md

Logic

Initial State:

• Lifts all at the bottom of the building
• People all outside the building
  • not waiting on an arrow
  • not in a lift

State 1:

These are performed simulataneously

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• Lift Thread
  1. Lift waits for a short amount of time (to allow people to enter the building)
  2. If no one is in the lift, it calls get_into_lift()
  3. get_into_lift() checks if someone is waiting on the up arrow semaphore
  4. Two things must then happen:
     • First, the lift must update the lift that currently is on that floor
     • Second, the lift must signal to a passenger that it may enter.

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• Person Thread 1.