data class Person(val name: String) {
    var age: Int = 0
}

fun main(args: Array<String>) {
    println(Person("Adam")) // Person(name=Adam)

    // Note: This also means that `age` will be excluded from the auto generated equals and hashCode methods.
    // So even though these people have different ages, they are treated as equal.
    // You may find a use case for this, but it is important to be aware of.
    val adam1 = Person("Adam")
    adam1.age = 20
    val adam2 = Person("Adam")
    adam2.age = 50
    println(adam1 == adam2) // true
    println(adam1.hashCode() == adam2.hashCode()) // true
}