Use Kotlin List, Loops, and builder pattern. Learned from Google Codelabs https://developer.android.com/codelabs/basic-android-kotlin-training-lists

KotlinList.kt

open class Item(val name: String, val price: Int)

class Noodles : Item("Noodles", 10){
   override fun toString(): String {
       return name
   }
}

class Vegetables(vararg val toppings: String) : Item("Vegetables", 5){
   override fun toString(): String {
       	if (toppings.isEmpty()) {
        	return "$name Chef's Choice"
        } else {
            return name + " " + toppings.joinToString()
        }
   }
} 

class Order(val orderNumber: Int){
    private val itemList = mutableListOf<Item>()
    
    fun addItem(newItem: Item): Order {
        itemList.add(newItem)
        return this
    }

    fun addAll(newItems: List<Item>): Order {
        itemList.addAll(newItems)
        return this
    }

   fun print() {
       	println("Order #${orderNumber}")
        var total = 0
        for (item in itemList) {
            println("${item}: $${item.price}")
            total += item.price
        }
        println("Total: $${total}")
   }    
}

fun main() {
    val ordersList = mutableListOf<Order>()

    // Add an item to an order
    val order1 = Order(1)
    order1.addItem(Noodles())
    ordersList.add(order1)

    // Add multiple items individually
    val order2 = Order(2)
    order2.addItem(Noodles())
    order2.addItem(Vegetables())
    ordersList.add(order2)

    // Add a list of items at one time
    val order3 = Order(3)
    val items = listOf(Noodles(), Vegetables("Carrots", "Beans", "Celery"))
    order3.addAll(items)
    ordersList.add(order3)

    // Use builder pattern
    val order4 = Order(4)
        .addItem(Noodles())
        .addItem(Vegetables("Cabbage", "Onion"))
    ordersList.add(order4)

    // Create and add order directly
    ordersList.add(
        Order(5)
            .addItem(Noodles())
            .addItem(Noodles())
            .addItem(Vegetables("Spinach"))
    )

    // Print out each order
    for (order in ordersList) {
        order.print()
        println()
    }
}