Test.kt

data class Student(
    val id: Int,
    val name: String,
    val surname: String
)
    
class StudentsFactory {
    var nextId = 0
    fun next(name: String, surname: String) =
        Student(nextId++, name, surname)
}
    
val factory = StudentsFactory()
val s1 = factory.next("Marcin", "Moskala")
println(s1) // Student(id=0, name=Marcin, Surname=Moskala)
val s2 = factory.next("Maja", "Markiewicz")
println(s2) // Student(id=1, name=Maja, Surname=Markiewicz)