Wow i can do that now.It is really clear thank you for helping me and sorry because i really hard to understand that
Don't worry about it. Everyone starts somewhere. Fully understanding these little things in the beginning can save a whole lot of pain down the road. There are actually people who don't care about how exactly their program runs as long as it's working, and when things go wild, they can't find the source of the problem, so whenever you feel unsure about how a piece of code works, track it down until it's clear. You can always ask, of course. That's what this community is for.