Hi,

I'm looking through the reference and still can't find a handy way to do this:

Basically, I've an array of 8 numbers.
I've got an if clause that states if i is true, check if abs(i-4) is false.
As an example: if array[7] is true, check if array[abs(7-4)], which is array[3] is false.

This works except that once the result of the subtraction goes past 0, it's out of bounds. I want it to loop back to 7. Eg, the sequence, if counting, would go: 3,2,1,0,7,6,5,4, etc...

I can think of a few long winded ways of doing this, but I'm trying to avoid doing these as they may lead to a big mess of code further down the road.

The section of the code this is relavant to is:
Code:

for (int i=0; i < 8; i++) {
          if (layerOne[i] == true) {
            if (layerTwo[i*2] == true) {
              if (layerOne[abs(i-4)] == false) {
                checkOne = true; // theres 3 pixels in a row, starting at currColor, but not going the other way.
                ellipse(x,y,5,5);
              }
            }
          }
 

Thanks.

Hi Cedric, thanks for the input.

I'm fine with the concept of putting in another if statement that says if i < 0, i = 7 and so on and so forth. I can  solve this problem already in long-winded ways, but that's a problem in itself and why I wrote this question. I'm hoping I've missed a really simple way of doing this before I start doubling up my code just to get numbers to loop back to the end of a sequence.

Thanks again.

Something like:
Code:

for (int i = 0; i < 8; i++) {
  if (layerOne[i] && layerTwo[i*2] && !layerOne[(i + 4) % 8]) {
    checkOne = true;
    ellipse(x,y,5,5);
  }
} 

(untested)

That seems to work perfectly at the moment, thanks again PhiLho. It's been so long since I thought about the concept of remainders...  remind me if this is correct: 120 divided by 100 is 1 times, remainder 20. Whereas 20 divided by 100 is 0 times, remainder 20. Correct?

Great, I'll keep it in mind. Thanks again.