// Immutable User in Scala (Using Case Classes and Immutable Fields)
//
// Scala enforces immutability naturally:
//
// 1. `val` → immutable variable binding
// 2. `case class` → fields are immutable by default
// 3. No setters → no mutation path
// 4. Copy method → creates new modified instances without changing the original
//
// This makes Scala one of the strongest JVM languages for immutability.
//
// Immutable User using a case class
case class User(id: Int, name: String)
object Main {
def main(args: Array[String]): Unit = {
// Immutable user (val + case class)
val user = User(42, "Sophia")
println(s"ID: ${user.id}")
println(s"Name: ${user.name}")
// Attempt 1: modify id
// user.id = 100 // ERROR: Reassignment to val id (fields are immutable)
// Attempt 2: modify name
// user.name = "Tim" // ERROR: Reassignment to val name
// Instead, Scala uses copy() to create a new modified instance
val updatedUser = user.copy(name = "Tim")
println(s"Updated Name (new instance): ${updatedUser.name}")
// Original remains unchanged
println(s"Original Name: ${user.name}")
}
}
/*
run:
ID: 42
Name: Sophia
Updated Name (new instance): Tim
Original Name: Sophia
*/
