Kotlin Programming Cookbook

How to do it…

Now, let's look at how to create global variables in Kotlin. There are two ways to do it. Let's look at them one by one:

1. One way to do it is by declaring it under the class declaration. We can use var declaration, like this:

fun main(args: Array<String>) {    var student:Student?=null}

However, this approach will result in testing for nullability whenever you use it:

println(student?.age)

2. To prevent this, you can declare and initialize it using val, but that will result in an immutable variable, which might not be the desired behavior.
3. Another way to declare a global variable is by using the lateinit modifier. Here's how the preceding code will look:

fun main(args: Array<String>) {    lateinit var student:Student student=Student() ...