val strNumber = "42"
val number1 = strNumber.toInt()
//number1 is 42

val number2 = strNumber.toIntOrNull()
if (number2 != null) {
    println("number2 is $number2")
}
//number2 is 42

val number3 = strNumber.toLong()
//number3 is 42

println("number1 is $number1")
println("number3 is $number3")