Data Classes in Kotlin

// Data class
data class User(
    val id: Int,
    val name: String,
    var email: String
)

val user = User(1, "Alice", "alice@example.com")
val copy = user.copy(email = "newemail@example.com")

// Destructuring
val (id, name, email) = user

// Generated methods
println(user.toString())  // User(id=1, name=Alice, email=alice@example.com)
println(user.hashCode())
println(user == copy)  // false (different email)

// Data class requirements
// - Primary constructor with at least one parameter
// - All parameters marked as val or var
// - Cannot be abstract, open, sealed, or inner