Published: 05 Jun, 2011

My Daughter’s First Pair Programming Session

My daughter was very disappointed that she lost a game of Chutes & Ladders. She hit the biggest slide, then the biggest ladder then tied my wife in race to roll a 1 – it was a very exciting game. After some tears we had the following conversation:

Daddy
I can see you’re very disappointed. What do you think we should do about it?
Piper
I want it so that I was the the winner of the game.
Daddy
Ok.
Piper
Wha?
Daddy
You’re the winner.
Piper
Pauses. Then starts to cry. I still feel frustrated!
Daddy
That’s because you didn’t really win.
Piper
We should play it again but I’ll win this time.
Daddy
Ok.
Piper
Wha?
Daddy
But I’m unclear on how to do it. Maybe you can help me figure it out.
Piper
When we play, I’ll win.
Daddy
Right. So you’ll spin the numbers and those numbers will make you win.
Piper
Yes.
Daddy
How do we make the spinner know you’re the one spinning it?
Piper
Pauses We’ll make a machine that knows.
Daddy
Cool idea! Where do we get that machine?
Piper
We have to make it.
Daddy
Ok. How do we make it?
Piper
We get blueprints like on Phineas and Ferb and follow the instructions.
Daddy
You know. My job is to make blueprints for a kind of machine that runs in a computer called a program.
Piper
Really?
Daddy
Yep. Do you want to help me make a machine that plays a game where you always win?
Piper
Big Grin Sure!
Daddy
Begins Coding Ok. So how will it know if you’re playing?
Piper
It’ll ask our own names.
Daddy
Ok. So you’ll type it in?
Piper
Yes.
Daddy
And what if I was to type your name in? (I’m hoping she’ll invent passwords)
Piper
Pauses That’s not nice to do.
Daddy
No it’s not. So we type our names in and if you’re playing, you win?
Piper
Yep.
Daddy
types for a few minutes Ok. Let’s play!

We played the game about 10 times. Each time we played, she won. Now I have to admit that my goal was that she would discover that a rigged game wasn’t fun to win and that winning is fun because there is losing. But each time she won, she beamed with happiness. A bit disappointed I talked her thru how the program worked. Then content at her perfect success at our game she said “I’m ready for books now.”

Here’s the program we wrote:

print "How many players? "
$stdout.flush
number_of_players = gets.strip.to_i

player_names = []
number_of_players.times do
  print "What is the name of player ##{player_names.size + 1}? "
  player_names << gets.strip
end

if piper = player_names.grep(/piper/i).first
  puts "#{piper} wins!!!"
else
  puts "#{player_names[(number_of_players * rand).to_i]} wins!!!"
end

And some of the console log:

[master][~/Projects/piper] ruby only_piper_wins.rb 
How many players? 2
What is the name of player #1? daddy
What is the name of player #2? piper
piper wins!!!
[master][~/Projects/piper] ruby only_piper_wins.rb
How many players? 3
What is the name of player #1? mommy
What is the name of player #2? daddy
What is the name of player #3? piper
piper wins!!!
[master][~/Projects/piper] ruby only_piper_wins.rb
How many players? 3
What is the name of player #1? mommy  
What is the name of player #2? chris
What is the name of player #3? piper
piper wins!!!
[master][~/Projects/piper] ruby only_piper_wins.rb
How many players? 2
What is the name of player #1? daddy
What is the name of player #2? mommy
daddy wins!!!
[master][~/Projects/piper] ruby only_piper_wins.rb
How many players? 3
What is the name of player #1? mommy
What is the name of player #2? piper
What is the name of player #3? daddy
piper wins!!!
[master][~/Projects/piper] ruby only_piper_wins.rb
How many players? 2
What is the name of player #1? mmmommmy
What is the name of player #2? piper
piper wins!!!
# I mention I'm sad that I never win so she changes her name to mommy
[master][~/Projects/piper] ruby only_piper_wins.rb
How many players? 2
What is the name of player #1? mommy
What is the name of player #2? daddy
mommy wins!!!
[master][~/Projects/piper] ruby only_piper_wins.rb
How many players? 2
What is the name of player #1? daddy
What is the name of player #2? mommy
mommy wins!!!