Design an Elevator Control System (OOD)

Problem Design an object-oriented elevator control system for a multi-floor building with multiple elevator cars.

Requirements

• Accept a floor request from inside a car and an up/down hall call from outside.
• Coordinate multiple elevators with dispatch logic deciding which car serves a call.
• Model the door, motor, and elevator state transitions.

Areas to design

• The class breakdown and responsibilities (cars, requests, dispatcher, buttons).
• The state model that keeps door/movement invariants safe.
• The scheduling strategy that decides a car's next stop and which car answers a hall call.