Basic sales tax is applicable at a rate of 10% on all goods, except books, food, and medical products that are exempt. Import duty is an additional sales tax applicable on all imported goods at a rate of 5%, with no exemptions.
When I purchase items I receive a receipt which lists the name of all the items and their price (including tax), finishing with the total cost of the items, and the total amounts of sales taxes paid. The rounding rules for sales tax are that for a tax rate of n%, a shelf price of p contains (np/100 rounded up to the nearest 0.05) amount of sales tax.
Write an application that prints out the receipt details for these shopping baskets...
Input 1:
1 book at 12.49
1 music CD at 14.99
1 chocolate bar at 0.85
Input 2:
1 imported box of chocolates at 10.00
1 imported bottle of perfume at 47.50
Input 3:
1 imported bottle of perfume at 27.99
1 bottle of perfume at 18.99
1 packet of headache pills at 9.75
1 box of imported chocolates at 11.25
Output 1:
1 book : 12.49
1 music CD: 16.49
1 chocolate bar: 0.85
Sales Taxes: 1.50
Total: 29.83
Output 2:
1 imported box of chocolates: 10.50
1 imported bottle of perfume: 54.65
Sales Taxes: 7.65
Total: 65.15
Output 3:
1 imported bottle of perfume: 32.19
1 bottle of perfume: 20.89
1 packet of headache pills: 9.75
1 imported box of chocolates: 11.85
Sales Taxes: 6.70
Total: 74.68
This is for the Thoughtworks Coding Challenege, I am applying for a Junior Consultant Role / Entry Level Developer.
ruby generate.rb <filename>.txt
Note: The text file must be placed in the input folder. 3 files from the problem have been included for your convenience.
- input1.txt
- input2.txt
- input3.txt
Tests were done with rspec.
rspec spec/<filename>.rb - individual test
rspec - run all tests
- input_spec.rb - tests for file input
- transform_spec.rb - tests for file input being parsed correctly
- calculator_spec.rb - tests for calculating sales tax and totals
- printer_spec.rb - tests for printing the output
- run_tax.rb - tests that the 3 input files output correctly
- The input text file follows the following syntax:
1 book at 12.49 qty, name, "at", price
- Product Quantity is a positive integer
- Price is a positive number
- Items to be excluded from the goods sales tax (10%) is included in a text file called
exclusions.txtplaced in the input folder. - Imported items have the word
importedin them.
This is a high level overview of the script:
+---------+
|INPUT TXT|+---------+ +---------------+
+---------+ +-------->|Input |
| |---------------|
+--------------+ | | Converts files|
|EXCLUSIONS TXT|+----+ | into an array|
+--------------+ +---+-----------+
|
|
|
v
+--------------------+ +-----------------------------+
|Transform +------------>|Calculator |
|--------------------| |-----------------------------|
| Takes the array and| | Updates the array of hashes |
| parses it into an | | for good_tax, import_tax, |
| array of hashes | | sales_tax, total_all |
| | +-+---------------------------+
| Flags true or false| |
| for good/import | |
| taxes | |
| | |
| Returns items with | |
| a qty greater than| |
| zero | |
+--------------------+ |
|
|
v
+-------------------------------+
| Printer |
|-------------------------------|
| Takes the updated array from |
| Calculator and proceeds to |
| generate a new array of the |
| items, sales_total, and of |
| the entire total |
| |
| Prints the array |
+-------------------------------+
1 book at 1.99
1 book at 0.99
Essentially the input text file, gets converted into an array:
[ "1 book at 1.99", "1 book at 0.99" ]
There is a simple validation to make sure there is clean input. Of the strings only the strings that have the word "at" are selected. Any strings without "at" are ignored. For the parsing process, "at" is essential.
Where it then gets split up:
[ ["1", "book", "at" ,"1.99"], ["1", "book", "at", "0.99"] ]
After the array is split up, the array is converted into an hash. "at" becomes very useful here because it allows the script to determine the positioning of the items.
["1", "book", "at", "1.99"]
index: 0, 1, 2, 3
By knowing where "at" is located, which is index 2, we can assume anything between index 0 (which would be qty) and index 2 ("at") is the item name (index 0+1 to index 2-1). The price would be located at index 3 (index 2+1).
So a hash is built with the following:
name: string
qty: integer
price: float
good: boolean
import: boolean
good_tax: float
import_tax: float
sales_tax: float
total: float
good and import act as flags which signal whether or not good tax or import tax should be applied.
good_tax, import_tax, sales_tax, are initially set to 0.0 and will be updated via calculator. Total is simply set to qty * price and will be updated by calculator.
As I was writing this, I broke the application into 4 major components:
Input- where a file is taken and in and broken down into an arrayTransform- where that array is taken and parsed into an array of hashesCalculator- where that array of hashes is updated with the correct totalsPrinter- where the output is displayed
Warning, this attempt is not very OOP and uses too many hashes. Naming choices are also poor.
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