---

fun main() {
    val firstName: String? = "Алексей"
    val lastName: String? = null
    val middleName: String? = "Петрович"

    fun formatFullName(
        firstName: String?,
        lastName: String?,
        middleName: String?
    ): String {

        val first = firstName ?: "[не указано]"
        val last = lastName ?: "[не указано]"
        val middle = middleName ?: "[не указано]"

        return "$last $first $middle"
    }

    println(formatFullName(firstName, lastName, middleName))

    println(formatFullName("Алексей", "Иванов", "Петрович"))
    println(formatFullName("Алексей", null, "Петрович"))
    println(formatFullName("Алексей", null, null))
    println(formatFullName(null, null, null))
}