This script was a code challenge for a London-based Fintech. I have obfuscated some words in this readme to prevent the code being find-able by other applicants, spoiling the challenge.
This shows a test-driven (TDD) approach. The code is clean, easily human-readable, and has been compartmentalised into sensible classes and methods. The algorithm chosen is one of the fastest available for solving this type of problem.
- The program must run from the command line and print a table to STDOUT .
- The first row and column of the table should have the N primes, with each cell containing the product of the primes for the corresponding row and column.
- Allow the user to specify different table sizes through a command line option. If the option is not used, the table should contain the first 10 primes by default.
- Consider complexity. How fast does your code run? How does it scale?
- Do not use the Prime class from the Ruby stdlib (write your own code).
- Write tests. Try to demonstrate TDD/BDD.
- If you’re using external dependencies please specify those dependencies and how to install them.
A Sieve of Eratosthenes algorithm quickly generate primes. A seperate table builder object prints the multiplication table to console.
To install, clone this repository and from the terminal run:
$ bundle install
To print the table of the first N pr1mes:
$ ruby lib/run.rb N
For example: $ ruby lib/run.rb 4 prints
2 3 5 7
2 4 6 10 14
3 6 9 15 21
5 10 15 25 35
7 14 21 35 49
if N is omitted, the script defaults to N=10.
$ rspec
$ bundle exec guard # Runs guard in terminal. Guard runs the relevant tests for a file when it is saved.
Note to self - does not need to be done now
https://github.com/guard/guard
https://github.com/guard/guard-rspec
$ bundle exec guard init # Initialises guard
$ bundle exec guard init rspec # Install rspec plugin for guard
https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes https://gist.github.com/loganhasson/8937903