We are going to start this tutorial by explaining the diferent ways in which we can name variables in Scala, by using the keyword var or val.
var denotes that it is a variable, and as such, its value can change in different points of our program. For example:
var myNewVariable = 4
... // some time later...
myNewVariable = 40
As we can se, we are using the same variable to hold two different values 4 and 40.
On the other hand, a val defines a value, which is something that will not change in the entire life of the application or real life. For example, the value 4 will never change, since it would make no sense that it meant something diffent.
val gravity = 9.81
If you ever try to modify a value, the compiler will throw and error and abort compilation.