bootiful-calculator

Challenge #2: Bootiful Calculator

Bespoke Bitcoin Solutions Ltd. thank you for your work - helping them find out the lowest bitcoin prices. They have now decided, in a bid to save money, they're going to stop buying calculators for the office and instead, they're going to use a central web-based calculator. Solution

Specifications

You must write a web application with 1 endpoint: /calculate. This endpoint will accept a POST request with the following body template:

POST /calculate
{
  "values": [5, 1, 20],
  "operation": "add",
  "type": "integer"
}

field	type	description
values	Array<Number>	A list of numbers, can be whole or decimal.
operation	String	The operation to perform, possible values are: add, sub, mul, div.
type	String	The type of the expected result, possible values are: integer, decimal, safe.

And will respond with a JSON object containing the result:

HTTP 200
{
  "result": 26
}

Or in the case of a user error:

HTTP 400
{
  "error": "error reason"
}

Types

The type field is important, it can be one of three values: integer, decimal, safe. Information about them is below:

value	description
integer	The values will be processed as whole numbers, any decimals passed into values should return an error.
decimal	The values will be processed as decimal numbers, 32-bits of precision will suffice.
safe	The values will be processed as safe decimals, you must ensure there are no floating-point precision errors when applying operations to safe decimals.

Operations

There are 4 operations this program will support:

operation	description	example
add	Will add all the values together	[5, 10, 2] => 17
sub	Will subtract all the values, starting at the left-most value, and ending at the right-most value.	[10, 2, 2] => 6
mul	Will multiply all the values together.	[5, 5, 2] => 50
div	Will divide all the values, starting at the left-most value, and ending at the right-most value.	[10, 1, 2] => 5

Rules

You will be scored on the following criteria:

• Good use of design patterns.
• Unit/Integration testing.
• Code readability.
• Code runnability.

The code will be pushed to a public git repo.

Other Rules:

• Please only submit Java, Kotlin or Groovy code.

• Please use Gradle or Maven, to make it easier for us to run your code.

• Feel free to use any frameworks/libraries you like.

Good luck!