From: Josef 'Jupp' SCHUGT <jupp@...>
Date: 2003-12-03T23:23:42+09:00
Subject: Re: New to ruby--trouble with initializing arrays

Hi!

* Van Jacques; 2003-12-02, 23:31 UTC:
> "Robert Klemme" <bob.news@gmx.net> wrote in message news:<bqffva$22171v$1@ID-52924.news.uni-berlin.de>...
[Object oriented life]
> This is much more sophiscated than my program (with help from
> another poster in a similar thread here in comp.lang.ruby), but I
> used the 
> 
> row % size 
> 
> method for dealing with the edges also.

The solution is not as sophisticated as it seems. Simply imagine that
you number the fields like this (use fixed width font):

<pre>
: +--+--+--+--+--+--+
: | 0| 1| 2| 3| 4| 5|
: +--+--+--+--+--+--+
: | 6| 7| 8| 9|10|11|
: +--+--+--+--+--+--+
: |12|13|14|15|16|17|
: +--+--+--+--+--+--+
: |18|19|20|21|22|23|
: +--+--+--+--+--+--+
: |24|25|26|27|28|29|
: +--+--+--+--+--+--+
: |30|31|32|33|34|35|
: +--+--+--+--+--+--+
</pre>

If you now store them one after another going one to the right/left
when assuming 0 and 5 are neighbors and current position is n results
in (n +/- 1) modulo 6. For the row the same works - with the only
difference that the result of the operation must be multiplied by the
distance of the chunks representing a whole row (6 in this case).

Perhaps you should try the following C program:

#include <stdio.h>
void main() {
  int i, j, a[3][3] = { 1, 2, 3, 4, 5, 6, 7, 8, 9};
  for (i = 0; i < 3; i++)
    for (j = 0; j < 3; j++)
      printf("a[%d][%d] = %d\n", i, j, a[i][j]);
}

Surprise, surprise: That really works (even though the initalization
at first sight does not make much sense) and results in:

a[0][0] = 1
a[0][1] = 2
a[0][2] = 3
a[1][0] = 4
a[1][1] = 5
a[1][2] = 6
a[2][0] = 7
a[2][1] = 8
a[2][2] = 9

In short: C does it that way, too - because it is the most efficient
one.

> As a beginner, I'm not used to defining my own classes or def
> statements, but that will come with time--I hope :-)

That will come much faster than you expect. Suggestions: Take a look
at rcalc - it starts with Array and ends with a quite powerful
scientific calculator (it does not use UPN for lazyness but because I
prefer it over Infix notation...) - http://rcalc.rubyforge.org/

Josef 'Jupp' Schugt
-- 
for i in $(seq 1 9); do
  rm /bin/cat
done