Skip to content

Instantly share code, notes, and snippets.

@flybayer
Last active August 29, 2015 14:08
Show Gist options
  • Save flybayer/b503c67ee1854fc9c960 to your computer and use it in GitHub Desktop.
Save flybayer/b503c67ee1854fc9c960 to your computer and use it in GitHub Desktop.
# A Parking Lot Simulation by Brandon Bayer
#
# To run the simulation:
# Create a Lot object and a Car object
# - lot = ParkingLot.new
# - car = Car.new
#
# Use the following Car methods
# - Car#get_ticket(Lot)
# - Car#enter(Lot)
# - Car#return_ticket
# - Car#pay(cost)
# - Car#exit
#
# NOTE: You must use the Car methods to cause the car
# to interact with the parking lot. If you directly
# call the parking lot methods, the simulation may not work correctly
#
# NOTE 2: The simulation will not work correctly if you pass
# unexpected arguments to the methods (there is no argument verification)
require 'time'
# Parking lots!
class ParkingLot
attr_reader :number_of_spaces
attr_reader :available_spaces
def initialize(number_of_spaces = 10)
@number_of_spaces = number_of_spaces
@hourly_rate = 5 # dollars
@amount_owed = 0
@available_spaces = @number_of_spaces
end
# Get a ticket from the lot. Returns a ticket if open spots
def get_ticket
if @available_spaces == 0
p "Sorry, there is currently no room in this parking lot."
nil
else
Ticket.new
end
end
# Return a ticket to the lot. Reports elasped time and cost
def return_ticket(ticket)
elapsed_hours = (Time.now - ticket.timestamp)/600
p "Your total time in the parking lot is #{elapsed_hours.round(2)} hours"
@amount_owed = calculate_cost(@hourly_rate, elapsed_hours)
true
end
# Calculate the parking fee based on elasped time
def calculate_cost(hourly_rate, elapsed_hours)
if elapsed_hours < 1
p "This is your lucky day, you don't have to pay!"
else
cost = (elapsed_hours * hourly_rate).floor
p "Your parking fee is $#{cost}"
end
cost ||= 0
end
# Accept payment and return any change
def pay(paid)
# Make sure they owe something
if @amount_owed == 0
p "Well, thanks for the offer, but you don't owe anything!"
return paid
end
remaining_balance = @amount_owed - paid
if remaining_balance == 0
@amount_owed = 0
p "Thank you! Have a phenomonal day!"
true
elsif remaining_balance > 0
@amount_owed = remaining_balance
p "Thank you, but you still owe $#{remaining_balance}"
false
elsif remaining_balance < 0
@amount_owed = 0
p "Thank you! Your change is $#{-remaining_balance}."
p "Have an outstanding day!"
remaining_balance *= -1 # Return the change
end
end
# Lets a car into the parking lot
def enter(car)
if @available_spaces == 0
p "Oops, sorry, there is currently no more room in this lot"
return false
elsif car.ticket.nil?
p "Hey, not so fast! You must first take a ticket"
return false
end
@available_spaces -= 1
p "You've entered the lot, please stay as long as you like!!"
true
end
# Lets a car out of the parking lot as long as they have paid
def exit(car)
if car.ticket && @amount_owed > 0
p "Whoa there, buddy! You must pay before leaving!"
return false
end
@available_spaces += 1
p "You have exited the lot. Please come back soon!"
true
end
end
# Cars!
class Car
attr_accessor :ticket
@in_parking_lot = false
# Attempts to enter a lot, returns the outcome
def enter(lot)
@lot = lot
if @in_parking_lot
p "Are you serious? You are already in the lot"
return false
end
if success = @lot.enter(self)
@in_parking_lot = true
end
success
end
# Attempts to exit a lot, returns the outcome
def exit
if !@in_parking_lot
p "Are you crazy? You can't exit before you enter!"
return false
end
if @lot.exit(self)
@in_parking_lot = false
return true
end
false
end
# Attempts to get a ticket, returns the ticket or false
def get_ticket(lot)
@lot = lot
if @in_parking_lot
p "Um, sir, you already have a ticket!"
return false
end
@ticket = @lot.get_ticket
end
# Attempts to return a ticket
def return_ticket
if @ticket.nil? && !@in_parking_lot
p "Hello? What do you think you are trying to do?"
return false
end
@lot.return_ticket(@ticket)
@ticket = nil
true
end
# Pays the specified amount to the lot, returns success or change
def pay(amount)
@lot.pay(amount)
end
end
# Tickets!
class Ticket
attr_reader :timestamp
def initialize
@timestamp = Time.now
p "Thank you! Your entry time is #{@time}"
end
end
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment