wrapping an array index seems impossible?

OpinionatedGamer

I have an array of 2 guns and an array index variable called gun_index that is incremented up or down by 1 when I press the arrow keys. However, if gun index gets higher than the array length, i need it to go back to 0, and the same if it gets too low. I believe this needs to be done with a wrapf function.

I wrote this:

gun_index = wrapf(gun_index ,0, gun_array.size() - 1)

this isn't working. If i press up arrow, the index equals 1 no matter how many times I press it. If I press down arrow, the index equals -1.

If I remove the -1 from my code, pressing the down arrow will cycle through the index correctly, but now I have the problem of pressing up being able to cause the index to reach a higher number than the array can take, thus getting an error.

I have no idea why the first line of code doesn't work and the second does, what is going on and how do i fix it?

cybereality

Not sure that is the right function. You can do it like this:

gun_index = (gun_index + 1) % gun_array.size()

OpinionatedGamer

Thanks, that worked!

xyz

You can also use wrapi(). wrapf() is for floating point numbers and may cause rounding problems when return value is cast to an integer index.

OpinionatedGamer

Thanks, good to know. =)