Scheduled lift

[ambush]

hi

how to get started to design a program for a lift and visualize it.

for example

no. of floors is 4

no. of users is 26

functionality includes scheduling lift at a floor by the user.The user inputs floor he has to reach, and time.

[Gribouillis]

You can start thinking about the data that describe the state of the system at a given moment. I would say this data comprises which buttons are lit in the lift, which buttons are lit on the floors, the lift's current position and direction. Then think about the events that may change this data.