int i; is a declaration. Not the remarkable, dramatic kind of declaration you’d expect from Gandalf or William Wallace; it’s just a piece of programming code declaring a variable called ‘i’ to be of type integer. Just a number.
i has to be the most commonly used variable among c-type languages. I have used it a hundred thousand times and more; only recently did the meaning really strike me. i. Just a number. Just like a million million other ‘i’s out there.