Please consider the section about deinit and Site:

class Site{
    let id: Int

    init(_ id: Int){
        self.id = id;
        print("init! id: \(id)")
    }

    deinit{
        print("All your DEINIT are belong to us!! id:\(id)")
    }
}

Now Paul made a for-loop where expectedly init and deinit for all created Sites were called.

for i in 42...45{
        let site = Site(i)
    }

However, i tried declaring the object outside the for loop like this:

    var site: Site;
    for i in 51...53{
        site = Site(i)
    }

I expected that the deinit to be called for Sites 51 and 52, but that the site variable would have a value (an object with the id 53) after the loop but if i try to print it like this:

print("what value has Site: (site.id)")

i get an error message about the variable being used before it is initialized?

I don't get this, could someone enlighten me?