import java.util.*
import kotlin.collections.ArrayList
import kotlin.collections.HashMap

data class Product(
    val id: Int = 0,
    val name: String
)

data class Category (
    val id: Int = 0,
    val name: String,
    val products: MutableList<Product>
)

fun Category.addProduct(product: Product) {
    this.products.add(product);
}

fun main() {
    val categoryMap = HashMap<Int, Category>()
    categoryMap[1] = Category(
        1, "category1", ArrayList()
    )
    categoryMap.getValue(1).addProduct(
        Product(
            1,
            "product1"
        )
    )
    val scanner = Scanner(System.`in`)
    while (true) {
        print("nhap categoryId: ")
        val categoryId = scanner.nextInt()
        val category = categoryMap[categoryId]
        if (category != null) {
            println(category)
        }
    }
}