trait ISized {
    val size : Int
}

trait javaUtilIterator<T> : java.util.Iterator<T> {
    override fun remove() : Unit {
        throw UnsupportedOperationException()
    }
}

class MyIterator<T>(val array : ReadOnlyArray<T>) : javaUtilIterator<T> {
    private var index = 0

    override fun hasNext() : Boolean = index < array.size

    override fun next() : T = array.get(index++)
}

trait ReadOnlyArray<out T> : ISized, java.lang.Iterable<T> {
  fun get(index : Int) : T

  class Default {
    fun check(v: Any) =  v is T
  }

  override fun iterator() : java.util.Iterator<T> = MyIterator<T>(this)
}

trait WriteOnlyArray<in T> : ISized {
  fun set(index : Int, value : T) : Unit

  fun set(from: Int, count: Int, value: T) {
    for(i in from..from+count-1) {
        set(i, value)
    }
  }
}

class MutableArray<T>(length: Int, init : (Int) -> T) : ReadOnlyArray<T>, WriteOnlyArray<T> {
    private val array = Array<T>(length, init)

    override fun get(index : Int) : T = array[index]
    override fun set(index : Int, value : T) : Unit { array[index] = value }

    override val size : Int
        get() = array.size
}

fun box() : String {
    var a = MutableArray<Int> (4, {0})
    a [0] = 10
    a.set(1, 2, 13)
    a [3] = 40
    System.out?.println(a.iterator())
    System.out?.println(a.iterator().hasNext())
    for(el in a) {
        System.out?.println(el)
    }
    return "OK"
}