• Practice with functions, arrays, and objects.

1. Fork and clone this repository.
2. Create and checkout to a new branch, named homework.
3. When finished, add, commit and push to your fork to submit a pull request.

• Create a file named mbta.js to calculate the number of stops between stations on the "MBTA". Write additional functions used by this function as needed.
• The function takes the line and stop that a rider is getting on at and the line and stop that a rider is getting off at and returns the total number of stops for the trip.

There are 3 subway lines:

• Red
  • South Station
  • Park Street
  • Kendall
  • Central
  • Harvard
  • Porter
  • Davis
  • Alewife
• Green
  • Government Center
  • Park Street
  • Boylston
  • Arlington
  • Copley
  • Hynes
  • Kenmore
• Orange
  • North Station
  • Haymarket
  • Park Street
  • State
  • Downtown Crossing
  • Chinatown
  • Back Bay
  • Forest Hills
• All 3 subway lines intersect at Park Street, but there are no other intersection points.

The function will be invoked using the following pattern of arguments:

Start Line, Start Station, End Line, End Station

Here are some examples of how should be invoked.

stopsBetweenStations('Red', 'Alewife', 'Red', 'Alewife') // 0 stops
stopsBetweenStations('Red', 'Alewife', 'Red', 'South Station') // 7 stops
stopsBetweenStations('Red', 'South Station', 'Green', 'Kenmore') // 6 stops

• Consider diagramming the lines by sketching out the subway lines and their stops and intersection.
• Solve an easier problem first like only traveling on the Red line.
• Assume good input. Your function does not need to check the validity of the line or stop.
• Subway lines are keys in a dictionary (object literal), while the values are a list (array) of all the stops on each line.
• The key to the practice is to find the intersection of the lines at Park Street.

• Add validation so that the function only accepts Red, Green, and Orange for lines and only accepts the correct stops for each of their stops.
• Have the function print the line and stops as they ride the train.
• Example:

stopsBetweenStations('Red', 'South Station', 'Green', 'Copley') 

// Rider boards the train a Red Line and South Station.
// Rider arrives at Red Line and Park Street.
// Rider transfers from Red Line to Green Line at Park Street.
// Rider arrives at Green Line and Boylston.
// Rider arrives at Green Line and Arlington.
// Rider arrives at Green Line and Copley.
// Rider exits the train at Green Line and Copley.

1. All content is licensed under a CC­BY­NC­SA 4.0 license.
2. All software code is licensed under GNU GPLv3. For commercial use or alternative licensing, please contact [email protected].