Brain Fart on 2D arrays...

[Strahd]

I'm having a little brain fart on 2D arrays.

If I am going to declare a 2D array as

#define gridSize 20

int array[gridSize][gridSize];

And if I am going to access, (5,7), in (X,Y) cords. Then the correct format would be

array[7,5]

If that is the case, what would be a good suggestion, in not to confuse the X and Y cords? Would the following work?

#define gridSize 20

int x = gridSize;
int y = gridSize;

int array[x][y];

//now if I want (5,7), in (X,Y) cords
array[5][7]

Thank You in advance

[iMalc]

Remembering that x comes before y works good for me.

[SactoDoug]

Why not name your variable with "xy" in the name? Then every time you use it, you can't miss it.

Example:

int xyArray[gridSize][gridSize];
xyArray[5][7] = 3;

[claudiu]

Just remember this: if you want to go left to right you increment the second index. If you want to go top to bottom, you increment the first index.

[XenoReseller]

They don't actually represent real 2D structures, that's just an abstraction to help new programmers try to understand them. It really doesn't matter which you use for your x and why as long as you consistently use the same ones.

[Strahd]

Cool, thanks for the clarification, the up and down and left and right are great

I didn't have a C compiler installed on my laptop (and dam school doesn't allow downloads of X amount or greater), and I was working it out on pen and paper.

They don't actually represent real 2D structures, that's just an abstraction to help new programmers try to understand them. It really doesn't matter which you use for your x and why as long as you consistently use the same ones.

Actually for this it does sorta matter. This is actually part of a larger program.

I'm doing an AI for a Tron type game (light cycles), and as a twist there are two moving walls in the middle of the "grid."

We are given the tail positions in (x,y) cords, length, the NW corner (x,y cords), the length of the side the walls travels on, and speed. At the start of the game then it is our responsibility to keep track of the moving wall from that point on.

Up until now, I just kept the "square" path that the wall travels on a "no go zone," but I'm looking to change that, it's just a rather simple struct persay to feed details into my masking grid.