The document presents an introduction to Coding Dojo, emphasizing its role as a safe environment for practicing coding skills through various exercises called katas. It outlines the structure, goals, and values of the dojo, along with rules for participation and examples of prepared and randori katas. Furthermore, it includes specific coding challenges, such as converting integers to Roman numerals and calculating discounts on Harry Potter book purchases.

1. Coding Dojo Introduction Viet Nguyen 05 May, 2011 (based on slides of Nicholas H.Tollervey, Serge Rehem, Danilo T.Sato)

2. Agenda Coding Dojo introduction (30 minutes) Prepared Kata (30 minutes) Randori Kata (60 minutes)

3. Coding Dojo Introduction

4. “ Acquiring coding skills should be a continuous process...” http://codingdojo.org/

5. Coding Dojo – Motivation, Background What happens if lack of practice! Kata » Coding Dojo December 2004

6. Coding Dojo – What is it ? Dojo = A safe place to practice. A place to make mistakes and learn. Get together to work on a Kata, have fun and engage in deliberate practice

7. Coding Dojo – Goal Practice Learn techniques Improve techniques Not necessarily solve the problem

8. Coding Dojo – Values Safe environment New ideas are welcomed Collaborative / Non-competitive Open to all skill levels

9. Coding Dojo – General rules Computer + Projector TDD ( red >> green >> refactor ) Everyone should understand ALWAYS start from scratch

10. TDD & BabySteps red - green - refactor T D D

11. XP Practices

12. Parisian Dojo Rules 2mins: organise next dojo 30mins: retrospective on last dojo 10mins: decide the topic for this dojo 40mins: code (either “prepared” or “randori” kata) 10mins: half time break 40mins: code

13. Prepared Kata - A presenter shows how to solve the problem - Program from scratch - Using TDD + BabySteps - Each step must make sense to everyone present - Only interrupt if you don’t understand what’s going on

14. Randori Kata - Coding pair (pilot and co-pilot) - Each pair has a time slot (5-7 minutes) - Using TDD + BabySteps - At the end the pilot returns to the audience, the co-pilot becomes the new pilot and a new co-pilot volunteers from the audience

15. Coding Dojo – Don't Rush to finish the problem Use a real problem Go into flamewars on discussions Compete with other participants Allow people to get lost

16. Ethics If you know how to code, you should code If you're coding, everyone else has to understand what you're doing If you're the next to code, avoid breaking the flow If you're not coding, don't disturb who is If you have an idea, show it with code If you're stuck, ask for help

17. Prepared Kata

18. Roman Numerals Given a positive integer number determine its Roman numeral representation. The Roman letters are: I = 1 V = 5 X = 10 L = 50 C = 100 D = 500 M = 1000 You cannot write numerals like IM for 999. Wikipedia says "Modern Roman numerals are written by expressing each digit separately starting with the leftmost digit and skipping any digit with a value of zero." Examples: o) 1990 = MCMXC o) 2008 = MMVIII o) 99 = XCIX

19. Randori Kata

20. Harry Potter To try and encourage more sales of the 5 different Harry Potter books they sell, a bookshop has decided to offer discounts of multiple-book purchases. One copy of any of the five books costs 8 EUR . If, however, you buy two different books , you get a 5% discount on those two books. If you buy 3 different books , you get a 10% discount . If you buy 4 different books , you get a 20% discount. If you go the whole hog, and buy all 5 , you get a huge 25% discount . Note that if you buy, say, four books, of which 3 are different titles, you get a 10% discount on the 3 that form part of a set, but the fourth book still costs 8 EUR.

21. Harry Potter Your mission is to write a piece of code to calculate the price of any conceivable shopping basket (containing only Harry Potter books), giving as big a discount as possible. For example, how much does this basket of books cost? 2 copies of the first book 2 copies of the second book 2 copies of the third book 1 copy of the fourth book 1 copy of the fifth book Answer: 51.20 EUR

22. Questions