4 Final Variables
Final variables are declared using the val keyword (a final variable is a variable that can’t be reassigned)
The code on the left looks almost exactly like in the previous step, with one small change. The var was changed to val.
Try to run the code on the left, the compiler should complain on line 3, since we are trying to reassign x which is a val.
Exercise
Edit the code on the left, so it will run (either change theval back to var, remove the reassignment to x or assign the result of the expression in line 3 to a different val or var)
Note: Prefer using `val` over `var` (and immutable objects over mutable ones). There are many benefits that are out of the scope of this small tour.