코틀린스love다 - 이홍섭

[hongxeob]

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

// UserManagementSystem
class UserManagementSystem {
    companion object {
        const val ADULT_AGE: Int = 18
    }

    private val users = mutableListOf<User>()

    fun addUser(
        name: String,
        age: Int,
    ) {
        users.add(User(name, age))
    }

    fun getAdultUsers(): List<User> = users.filter { it.age >= ADULT_AGE }

    fun printUserNames() = users.forEach { println(it.name) }

    fun calculateAverageAge(): Double = users.map { it.age }.average()
}

// main
fun main() {
    val system = UserManagementSystem()

    // 사용자 추가
    val userList =
        listOf(
            User("옥순", 25),
            User("옥순", 25),
            User("상철", 17),
            User("영철", 30),
        )
    userList.forEach {
        system.addUser(it.name, it.age)
    }

    println("모든 사용자 이름:" + system.calculateAverageAge())

    println("\n성인 사용자:")
    system
        .getAdultUsers()
        .forEach {
            println("${it.name} : (${it.age}살)")
        }

    println("\n평균 나이: ${system.calculateAverageAge()}")
}