Recursion from chris pine's learning to program

gistfile1.rb

# 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,o],
         [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],
         [o,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 world[y][x] != ' land'
# Either it' s water or we already
# counted it, but either way, we don' t # want to count it now.
return 0
end
  #  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 )

Report erratum
RECURSION 83
  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)