it should be i (lower case letter) not the number 1. variables must always start use a letter up front. I try to avoid letter I and 1 and O and 0 just for that reason. best to avoid confusion is your can
An alternative to not using certain characters in variable names would be to find a better programming font to help distinguish those characters. It looks like OP is using
Courier New, which -- despite being the default on many Windows programs -- is a fairly bad programming font. Nearly no difference between
1 and
l and no slashed/dotted zero, among other issues. Consolas is barely any better and still has the same issue with the former, with the added issue of 8 and & being easier to confuse.
I'm insane and prefer the
Proggy family of fonts (specifically Crisp) for personal use, but I am partial to some of the larger, rounder fonts for general use.
Source Code Pro and
Ubuntu Mono are both great free options.