Imagine the scene. You are eleven years old, and in the five minutes before the end of the lesson, your Maths teacher decides he should make his class more “fun” by introducing a “game”.

He explains that he is going to point at each pupil in turn and ask them to say the next number in sequence, starting from one. The “fun” part is that if the number is divisible by three, you instead say “Fizz” and if it is divisible by five you say “Buzz”. So now your maths teacher is pointing at all of your classmatesin turn, and they happily shout“one!”, “two!”, “Fizz!”, “four!”, “Buzz!”… until he very deliberately points at you, fixing you with a steely gaze… time stands still, your mouth dries up, your palms become sweatier and sweatier until you finally manage to croak “Fizz!”. Doom is avoided, and the pointing finger moves on.

So of course in order to avoid embarrassment in front of your whole class, you have to get the full list printed out so you know what to say. Your class has about 33 pupils and he might go round three times before the bell rings for breaktime. Next maths lesson is on Thursday. Get coding!

Write a program that prints the numbers from 1 to 100. But for multiples of three print “Fizz” instead of the number and for the multiples of five print “Buzz”. For numbers which are multiples of both three and five print “FizzBuzz”.

Sample output: Kata: FizzBuzz 124

1

2

Fizz

4

Buzz

Fizz

7

8

Fizz

Buzz

11

Fizz

13

14

FizzBuzz

16

17

Fizz

19

Buzz

… etc up to 100

##Additional discussion points for the Retrospective • Is the code you have written clean? Are there any smells? • Did you refactor throughout or do it all at the end? • What if a new requirement came along that multiples of seven were “Whizz”? Could you add that without editing the existing code? (Cue discussion of the OpenClosed Principle) Kata: FizzBuzz 125 Ideas for after the Dojo • When you’ve got it all working for “Fizz” and “Buzz”, add “Whizz” for multiples of seven • Then add “Fizz” also for all numbers containing a 3 (eg 23, 53)

I find this an excellent kata for introducing beginners to TDD. It’s pretty straightforward to choose the order of test cases, work in small steps, and complete the whole exercise still leaving time for a decent retrospective.