In the screenshot I provided is already an implementation of how to check whether your index is valid or not. I also mentioned in the original reply (the one where the screenshot didn’t get attached for some reason) that the initial value of your int should be 0; since you will be starting at the first index of your array, which is always 0.
Variable names only matter when referencing them; their name doesn’t have anything to do with their value. You could have called your barrel00 “clownscar” and it would have still worked, as long as your variables actually have a reference in them.
Could you show me exactly where you set the variables barrel00 and so on?