Ruby Quiz <james / grayproductions.net> writes:

> by Brian Candler
>
> A version of Bingo played in the UK and some other countries is called "Housie".
> Players buy "books" of 6 tickets. Each ticket shows exactly 15 numbers, and in
> each book every number from 1 to 90 is used exactly once.

> 	1. Write a Ruby program which generates random individual tickets
> 	or
> 	2. Write a Ruby program which generates random complete books of tickets

When I first read the description, I thought "I already did that".
And in fact, I did.  Back in 2002, after only a few weeks using Ruby.

Have a look at the timestamp:
  -rw-r--r--  1 chris chris  1472 Jan 13  2002 bingo.rb
(Incidentally, that's my sisters birthday and I remember the guests
liked it.)

Anyway, my bingo solution from 2002 generates plain TeX output
suitable for printing.  The macro package is appended.
You'd call it like  ruby bingo.rb > entries.tex && pdftex bingo.tex.

Remember that this code has been untouched for 5 years, I wouldn't
necessarily code it that way today.

#!/usr/bin/env ruby
# -*- ruby -*-

Num = 14

class Bingo
  def initialize
    @width = 9
    @height = 3
    @field = [[0,0,0],[0,0,0],[0,0,0],
              [0,0,0],[0,0,0],[0,0,0],
              [0,0,0],[0,0,0],[0,0,0]]
  end
  
  def insert_numbers
    0.upto (@width-1) { |x|
      arr = ((x*10)..((x*10)+10)-1).to_a
      # Special cases: don't insert a 0, add 90 to the row with 80
      arr.delete(0)
      if arr.index(89) != nil
	arr = arr + [90]
      end

      0.upto (@height-1) { |y|
	r = arr[rand (arr.length)]
	arr.delete(r)
	@field[x][y] = r
      }
      @field[x].sort!
    }
  end

  def remove_some
    0.upto(@height-1) { |x|
      cnt = 0
      while cnt < 4 
	cnt+=1
	r = rand @field.length
	# The following crap eludes `three in a row'
	if @field[r][x] != nil &&
	    !((@field[r][0] == nil && @field[r][1] == nil) ||
 	      (@field[r][1] == nil && @field[r][2] == nil) ||
	      (@field[r][2] == nil && @field[r][0] == nil))
	  @field[r][x] = nil
	else
	  cnt-=1
	end
      end
      0.upto (@width-1) { |y|
      }
    }
    puts
  end

  def dump
    0.upto(@height-1) { |x|
      0.upto(@width-1) { |y|
	value = @field[y][x]
	if (0..9).to_a.index(value) != nil
	  value = '?' + value.to_s
	end
	if value == nil
	  value = '\X'
	end
	print "&& ", value, " "
      }
      if x != @height-1
	print "&\\nl\n"
      else
	print "&\\newsheet\n"
      end
    }
  end
end

Num.times {
  b = Bingo.new
  b.insert_numbers
  b.remove_some
  b.dump
}

% Print ``bingo'' sheets.

\font\mainfont=cmbx14
\mainfont

\newbox\strutbox
\setbox\strutbox=\hbox{\vrule height18.5pt depth13.5pt width0pt}
\def\strut{\relax\ifmmode\copy\strutbox\else\unhcopy\strutbox\fi}

\newdimen\onedigitwidth
\newdimen\digitwidth
\setbox0=\hbox{\mainfont0}
\onedigitwidth=\wd0
\setbox0=\hbox{\mainfont00}
\digitwidth=\wd0

\catcode`?=\active
\def?{\hbox to \onedigitwidth{}}
\def\X{\hbox to \digitwidth{\hfil$\bigcirc$\hfil}}

\begingroup

\tabskip=0pt
\offinterlineskip
\def\nl{\cr\noalign{\hrule}}
\def\newsheet{\cr\noalign{\hrule\vskip1cm\hrule}}
\halign{\strut#& \vrule#\tabskip=0.50em&
 \hfil#\hfil& \vrule#&\hfil#\hfil& \vrule#&\hfil#\hfil& \vrule#&
 \hfil#\hfil& \vrule#&\hfil#\hfil& \vrule#&\hfil#\hfil& \vrule#&
 \hfil#\hfil& \vrule#&\hfil#\hfil& \vrule#&\hfil#\hfil& \vrule#\tabskip=0pt\nl
\input entries.tex
\cr}

\endgroup

\bye


Enjoy,
-- 
Christian Neukirchen  <chneukirchen / gmail.com>  http://chneukirchen.org