Hey Fred,
Thanks for responding.
I was assuming that because of the line:
continent_size world, x, y
x defined the row and y defined the array value within that row. Is
that not true?
world[x][y] and world[y][x] only outputs the right value because 5, 5
is right smack in the middle of the array of arrays. If you change it
to 4, 3 and run it with world[x][y] and then try it with world[y][x]
you get two different values. I'm still not sure why the code starts
with x, y and then get's switched to [y][x] (I've pasted the original
below showing the [y][x] values. Am I just being dense?:
# These are just to make the map
# easier for me to read. "M" is
# visually more dense than "o".
M = ' land '
o = ' water '
world = [[o,o,o,o,o,o,o,o,o,o,o],
[o,o,o,o,M,M,o,o,o,o,o],
[o,o,o,o,o,o,o,o,M,M,M],
[o,o,o,M,o,o,o,o,o,M,o],
[o,o,o,M,o,M,M,o,o,o,o],
[o,o,o,o,M,M,M,M,o,o,o],
[o,o,o,M,M,M,M,M,M,M,o],
[o,o,o,M,M,o,M,M,M,o,o],
[o,o,o,o,o,o,M,M,o,o,o],
[M,M,o,o,o,M,o,o,o,o,o],
[o,o,o,o,o,o,o,o,o,o,o]]
def continent_size world, x, y
if x > 10 && y > 10
size = 0
else
if world[y][x] != ' land '
return 0
end
end
# Either it ' s water or we already
# counted it, but either way, we don ' t
# want to count it now.
# So first we count this tile...
size = 1
world[y][x] = ' counted land '
# ...then we count all of the
# neighboring eight tiles (and,
# of course, their neighbors by
# way of the recursion).
size = size + continent_size(world, x-1, y-1)
size = size + continent_size(world, x , y-1)
size = size + continent_size(world, x+1, y-1)
size = size + continent_size(world, x-1, y )
size = size + continent_size(world, x+1, y )
size = size + continent_size(world, x-1, y+1)
size = size + continent_size(world, x , y+1)
size = size + continent_size(world, x+1, y+1)
size
end
puts continent_size(world, 5, 5)
On Jan 23, 1:38 pm, Frederick Cheung <[email protected]>
wrote:
> On Jan 23, 8:34 pm, jordantheous <[email protected]> wrote:
>
> > *From Chris Pine, Learn to Program
>
> > Hey All --
> > In the below source code they array is called in the method as x, y,
> > but the "if" statements are looking to [y][x]. Can anyone explain to
> > me why they are switched? If you make them [x][y] it still outputs
> > the correct number (23).
> > Thanks in advance,
> > Jordan
>
> What you've got there is an array of rows (rather than an actual 2D
> construct), so it's normal that [y][x] first selects a row, then an
> element in that row.
>
> Fred
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