copy وequals

data class User(val name: String, val age: Int)

fun main() {
    val a = User("Alice", 30)
    val b = User("Alice", 30)
    println(a == b)
}

data class User(val name: String, val age: Int)

fun main() {
    val a = User("Alice", 30)
    val b = User("Alice", 31)
    println(a == b)
}

data class User(val name: String)

fun main() {
    val a = User("Alice")
    val b = User("Alice")
    println(a == b)  // values match
    println(a === b) // different instances
}

data class Point(val x: Int, val y: Int)

fun main() {
    val a = Point(1, 2)
    val b = Point(1, 2)
    println(a.hashCode() == b.hashCode())
}

data class User(val name: String, val age: Int)

fun main() {
    val a = User("Alice", 30)
    val b = a.copy()
    println(b)
    println(a == b)
}

data class User(val name: String, val age: Int)

fun main() {
    val a = User("Alice", 30)
    val older = a.copy(age = 31)
    println(a)
    println(older)
}

data class Account(val owner: String, val balance: Int)

fun main() {
    val original = Account("Sam", 100)
    val updated = original.copy(balance = 150)
    println(original.balance)
    println(updated.balance)
}

data class Config(val volume: Int, val muted: Boolean)

fun main() {
    val base = Config(50, false)
    val result = base.copy(volume = 70).copy(muted = true)
    println(result)
}

data class User(val name: String) {
    var note: String = "none"
}

fun main() {
    val a = User("Alice")
    a.note = "VIP"
    val b = a.copy()
    println(b.note) // back to default
}

data class User(val name: String, val age: Int)

fun main() {
    val a = User("Alice", 30)
    val b = a.copy(name = "Alicia")
    println(a == b)
    println(b)
}