The script lib/driving_history.rb accepts an input file of the format
Driver Dan
Driver Alex
Driver Bob
Trip Dan 07:15 07:45 17.3
Trip Dan 06:12 06:32 21.8
Trip Alex 12:01 13:16 42.0
and prints a summary report in the format
Alex: 42 miles @ 34 mph
Dan: 39 miles @ 47 mph
Bob: 0 miles
The report will also be saved to a file in the root directory of the project named:
report.txt.
From the root directory of this project run:
ruby lib/driving_history.rb lib/input.txt
You may substitute lib/input.txt for a different file of the expected format.
The script uses three objects to store and process the input file: Report, Driver and Trip. Separate objects and methods were chosen to make testing and debugging easier as well as provide an intuitive separation of concerns.
A new Report is initialzed with an input file. An instance method on a Report can then be called to process this input file. This processing creates various instances of Drivers and Trips according to the information in the input file.
The attribute on a Report object named drivers is a Hash; the key is the name of a Driver and the value is the corresponding Driver object. A Hash was chosen so that a Driver can quickly be found when a new Trip needs to be added.
Each Driver has an attribute trips which is a simple Array of Trip objects that the Driver took according to the input file. A new Trip should be added to the Driver using the add_trip instance method. This method updates the total_distance, total_time and avg_speed for the Driver in addition to adding the Trip to the trips array. Precalculation was chosen so that sorting drivers by the total distance they have driven will only require sorting by the Driver attribute total_distance, saving us from performing on-the-fly calculations of total distances that would require nested iterations over each Driver's trips array.
Finally, the method create_report can be called on an instance of Report. This will print output the console as well as saving the report to the file report.txt. The output summarizes the total distance and average speed for each Driver with the list sorted by descending total distance.