How to do it...

Let's see how to type check an object in these steps:

1. Let's try a very basic example, trying is with string and integer. In this example, we will type check a string and an integer:

fun main(args: Array<String>) {
    var a : Any = 1
    var b : Any = "1"
    if (a is String) {
        println("a = $a is String")
    }
    else {
        println("a = $a is not String")
    }
    if (b is String) {
        println("b = $b is String")
    }
    else {
        println("b = $b is not String")
    }
}

2. Similarly, we can use !is to check whether the object is not of type String, like this:

fun main(args: Array<String>) {
    var b : Any = 1
    if (b !is String) {
        println("$b is not String")
    }
    else {
        println("$b is String")
    }
}

If you remember how when works in Kotlin, we do not need to put in the is keyword, because Kotlin has a feature of smart cast and throws an error if the compared objects are not of the same type.