Toy Robot
Toy Robot
About the Book
The Toy Robot exercise was originally developed by Jon Eaves. He explains why he did it in this blog post.
If you're a new Ruby developer who's gone through some basic Ruby tutorials and you're looking for the next thing to build your skills, this book is a great start. It covers the Toy Robot exercise from start to finish, testing with RSpec along the way.
The Toy Robot exercise is commonly used in interviews as the ways to solve it in any language are not as simple as they first may seem. This book covers one implementation of this exercise in Ruby. It is not intended to be the most perfect implementation of the Toy Robot exercise possible, but instead is my personal take on it.
The Toy What Now?
The Toy Robot! It's a very common interview exercise given to new programmers. Here's the variant of the problem's description that we use in the book:
The application is a simulation of a toy robot moving on a square tabletop, of dimensions 5 units x 5 units. There are no other obstructions on the table surface. The robot is free to roam around the surface of the table. Any movement that would result in the robot falling from the table is prevented, however further valid movement commands are still allowed.
The application reads a file using a name passed in the command line, the following commands are valid:
- PLACE X,Y,F
- MOVE
- LEFT
- RIGHT
- REPORT
Here's some rules for these commands:
- PLACE will put the toy robot on the table in position X,Y and facing NORTH, SOUTH, EAST or WEST.
- The origin (0,0) is the SOUTH WEST most corner.
- All commands are ignored until a valid PLACE is made.
- MOVE will move the toy robot one unit forward in the direction it is currently facing.
- LEFT and RIGHT rotates the robot 90 degrees in the specified direction without changing the position of the robot.
- REPORT announces the X,Y and F of the robot.
The file is assumed to have ASCII encoding. It is assumed that the PLACE command has only one space, that is PLACE 1, 2, NORTH is an invalid command. All commands must be in upcase, all lower and mixed case commands will be ignored.
---
All of that may seem a little bit overwhelming but if you break it down into little chunks and tackle those chunks one-at-a-time (like this book does!) it becomes much easier.
Table of Contents
- Introduction
-
The Toy Robot
- Simplifying the problem
- Setting up our project
-
The
MOVE
command - Moving left
- Moving north and south
- Moving in the right direction
- Turn left!
- Turn right!
-
The
REPORT
command -
The
PLACE
command - Reading commands
- Running commands
- Running the robot
- Verifying the toy robot’s behaviour
- Conclusion
The Leanpub 60-day 100% Happiness Guarantee
Within 60 days of purchase you can get a 100% refund on any Leanpub purchase, in two clicks.
See full terms
Do Well. Do Good.
Authors have earned$11,815,072writing, publishing and selling on Leanpub, earning 80% royalties while saving up to 25 million pounds of CO2 and up to 46,000 trees.
Learn more about writing on Leanpub
Free Updates. DRM Free.
If you buy a Leanpub book, you get free updates for as long as the author updates the book! Many authors use Leanpub to publish their books in-progress, while they are writing them. All readers get free updates, regardless of when they bought the book or how much they paid (including free).
Most Leanpub books are available in PDF (for computers) and EPUB (for phones, tablets and Kindle). The formats that a book includes are shown at the top right corner of this page.
Finally, Leanpub books don't have any DRM copy-protection nonsense, so you can easily read them on any supported device.
Learn more about Leanpub's ebook formats and where to read them
Top Books
Stratospheric
Tom Hombergs, Björn Wilmsmann, and Philip RiecksFrom Zero to Production with Spring Boot and AWS. All you need to know to get a Spring Boot application into production with AWS. No previous AWS knowledge required.
Go to stratospheric.dev for a tour of the contents.
C++20 - The Complete Guide
Nicolai M. JosuttisAll new language and library features of C++20 (for those who know previous C++ versions).
The book presents all new language and library features of C++20. Learn how this impacts day-to-day programming, to benefit in practice, to combine new features, and to avoid all new traps.
Buy early, pay less, free updates.
Other books:
OpenIntro Statistics
David Diez, Christopher Barr, Mine Cetinkaya-Rundel, and OpenIntroA complete foundation for Statistics, also serving as a foundation for Data Science.
Leanpub revenue supports OpenIntro (US-based nonprofit) so we can provide free desk copies to teachers interested in using OpenIntro Statistics in the classroom and expand the project to support free textbooks in other subjects.
More resources: openintro.org.
node-opcua by example
Etienne RossignonGet the best out of node-opcua through a set of documented examples by the author himself that will allow you to create stunning OPCUA Servers or Clients.
Advanced Web Application Architecture
Matthias NobackThe missing manual for making your web applications future-proof
Jetpack Compose internals
Jorge CastilloJetpack Compose is the future of Android UI. Master how it works internally and become a more efficient developer with it. You'll also find it valuable if you are not an Android dev. This book provides all the details to understand how the Compose compiler & runtime work, and how to create a client library using them.
Ansible for DevOps
Jeff GeerlingAnsible is a simple, but powerful, server and configuration management tool. Learn to use Ansible effectively, whether you manage one server—or thousands.
R Programming for Data Science
Roger D. PengThis book brings the fundamentals of R programming to you, using the same material developed as part of the industry-leading Johns Hopkins Data Science Specialization. The skills taught in this book will lay the foundation for you to begin your journey learning data science. Printed copies of this book are available through Lulu.
Maîtriser Apache JMeter
Philippe Mouawad, Bruno Demion (Milamber), and Antonio Gomes RodriguesToute la puissance d'Apache JMeter expliquée par ses commiteurs et utilisateurs experts. De l'intégration continue en passant par le Cloud, vous découvrirez comment intégrer JMeter à vos processus "Agile" et Devops.
If you're looking for the newer english version of this book, go to Master JMeter : From load testing to DevOps
D3 Start to Finish
Peter CookD3 Start to Finish shows you how to build a custom, interactive and beautiful data visualisation using the JavaScript library D3.js (versions 6 & 7).
The book covers D3.js concepts such as selections, joins, requests, scale functions, events & transitions. You'll put these concepts into practice by building a custom, interactive data visualisation.
Top Bundles
- #1
CCIE Service Provider Ultimate Study Bundle
2 Books
Piotr Jablonski, Lukasz Bromirski, and Nick Russo have joined forces to deliver the only CCIE Service Provider training resource you'll ever need. This bundle contains a detailed and challenging collection of workbook labs, plus an extensively detailed technical reference guide. All of us have earned the CCIE Service Provider certification... - #2
Software Architecture
2 Books
"Software Architecture for Developers" is a practical and pragmatic guide to modern, lightweight software architecture, specifically aimed at developers. You'll learn:The essence of software architecture.Why the software architecture role should include coding, coaching and collaboration.The things that you really need to think about before... - #4
Pattern-Oriented Memory Forensics and Malware Detection
2 Books
This training bundle for security engineers and researchers, malware and memory forensics analysts includes two accelerated training courses for Windows memory dump analysis using WinDbg. It is also useful for technical support and escalation engineers who analyze memory dumps from complex software environments and need to check for possible... - #7
Retromat eBook Bundle for Agile Retrospectives
2 Books
If you facilitate retrospectives this bundle is for you: "Plans for Retrospectives" helps beginners learn the lay of the land with tried-and-true plans. Once you know your way around, "Run great agile retrospectives" contains all 135+ activities in Retromat for you to mix and match. - #8
Static Analysis and Automated Refactoring
2 Books
As PHP developers we are living in the "Age of Static Analysis". We can use a tool like PHPStan to learn about potential bugs before we ship our code to production, and we can enforce our team's programming standards using custom PHPStan rules. Recipes for Decoupling by Matthias Noback teaches you in great detail how to do this, while also... - #10
Practical FP in Scala + Functional event-driven architecture
2 Books
Practical FP in Scala (A hands-on approach) & Functional event-driven architecture, aka FEDA, (Powered by Scala 3), together as a bundle! The content of PFP in Scala is a requirement to understand FEDA so why not take advantage of this bundle!?