It only works when the variables are the same type. e.g. here i and j are both int.

I did not know about that ...

Hint: It pays to re-visit the language spec sometimes. There are lots of little things that are useful but maybe you don't see them much in common use. Do it now. You will quickly learn something else you didn't know about...

I did not know about that you could use two different variables in the for loop like that. You will have a better coding career than me. Props

Not sure what you mean... It's just common syntax

https://docs.oracle.com/javase/specs/jls/se8/html/jls-14.html#jls-14.14.1

How did you learn to code the for loop like that?