Looping in a spiral

Question

A friend was in need of an algorithm that would let him loop through the elements of an NxM matrix (N and M are odd). I came up with a solution, but I wanted to see if my fe

Answer 1

Here is my solution (In Ruby)

def spiral(xDim, yDim)
   sx = xDim / 2
   sy = yDim / 2

   cx = cy = 0
   direction = distance = 1

   yield(cx,cy)
   while(cx.abs <= sx || cy.abs <= sy)
      distance.times { cx += direction; yield(cx,cy) if(cx.abs <= sx && cy.abs <= sy); } 
      distance.times { cy += direction; yield(cx,cy) if(cx.abs <= sx && cy.abs <= sy); } 
      distance += 1
      direction *= -1
   end
end

spiral(5,3) { |x,y|
   print "(#{x},#{y}),"
}