I noticed that the above is incorrect. You say that the row (Y coordinate) is division (/) but in the example you use division on the X coordinate. I guess the example should be:
2D matrix coordinates are in format {row, column}, where the row number is always first.
So my answer was correct for mathematical standpoint. C++ uses same notation for its multi dimensional arrays. Using another notation will be misleading for others reading your code, because everyone will expect it to be consistent with standard behavior. http://en.wikipedia.org/wiki/Matrix_%28mathematics%29#Notation