KotlinTutorial.kt
fun main() {
    val user1 = User("Hans", 30)

    println("user name: ${user1.name}")
    println("user age: ${user1.age}")

    val user2 = User("Elfriede", 60)

    println("user name: ${user2.name}")
    println("user age: ${user2.age}")
}

class User(val name: String, var age: Int) {
}