From: Smgspices@...
Date: 2006-11-17T06:57:46+09:00
Subject: Beginner Needs Help

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I am new to Ruby and OOP although I have written programs in Forth; another  
world. As a learning project, I decided to duplicate something I had written 
in  Forth; namely a bridge hand dealer. I originally stored the hands in a  
3-dimensional binary array (hand, suit, cards). In cards, a set bit represented  
a particular card. I like the binary representation because it makes things 
like  searching for pairs or sequences, etc. easy with bit logic.
 
Here is what I have written so far:
 
class Carddeck
attr_writer :deck
def  initialize
@deck=Array.new
end

def  build_deck
0.upto(51) {|i|  @deck.push(i.divmod(13))}
# deck consists of 52 2-member  arrays, [suit, rank], 
# each representing a playing card.  In use, the first 
# 13 members is hand[0] and the next 13  are hand[1], etc.
# hand will be defined in a  subclass.
return @deck
end

def  shuffle_deck
@deck=@deck.sort_by{rand}
end
end

class Bridgehands < Carddeck
attr_writer :hands 
attr_reader :deck
def initialize
super
@hands = Array.new(4) {|idx|  Array.new(4)}
# hands is a 4 by 4 array for  player,suit
end

def  build_hands
self.shuffle_deck
0.upto(51) {|i| @hands[i/13][@deck[i][0]] += 0b1 <<  @deck[i][1]}
# The left side addresses a particular cell  in hands.
# The right side converts the card rank to a bit  shifted 
# to the position represented by the rank of the  card. 
# We cycle through the entire deck and let i/13 =  the hand.
return @hands
end
end
 
Carddeck works just fine but Bridgehands returns an error when I  enter:
 
bh = Bridgehands.new followed by bh.build_deck and then  bh.build_hands. to 
which it responds:
 
NoMethodError: undefined method `+' for  nil:NilClass
from (irb):92:in  `build_hands'
from (irb):92:in  `build_hands'
from  (irb):103
from :0
 
I'm going nuts.
 
Charles Gray -- Phoenix, AZ ... skype and google-talk user name:  tcykgreis
 

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