CODEWITHSUNDEEP
kotlin
user12595983
user12595983

Reputation: 147

Kotlin: Type inference failed. Expected type mismatch: inferred type is Pair<String, Int> but Pair<Product, Int> was expected

I wanna call run the following function addToCart() in the main, but such error appears, may i know how should i change my code? Thanks!

    fun addToCart(){
    println("Productname : ")
    var nameInput= readLine() ?: "-"
    println("Num of $nameInput ")
    var num = readLine()!!.toInt()
    var got : Product? = warehouse.getProductByName(nameInput)
    shoppingCart.addToList(nameInput, num)

}

class ShoppingCart () {
            private val productAndQuantityList = mutableListOf<Pair<Product, Int>>()
            fun addToList(name: String, quantity: Int){
                productAndQuantityList.add(Pair(name, quantity))
            }
        ....
        }

Upvotes: 1

Views: 1115

Answers (1)

jseteny
jseteny

Reputation: 420

I think you need not null checks before calling add.

fun addProductToCart(shoppingCart: ShoppingCart, warehouse: Warehouse) {
    println("Product name: ")
    var productName_E = readLine() ?: "-"
    println("No. of $productName_E ")
    var num = readLine()?.toInt()
    var got: Product? = warehouse.getProductByName(productName_E)
    if (num != null && got != null) {
        shoppingCart.productAndQuantityList.add(Pair(first = got, second = num))
    }
}

Your ShoppingCart class should be something like the class below.

class ShoppingCart {

    val productAndQuantityList = mutableListOf<kotlin.Pair<Product, Int>>()
    ...
}

Upvotes: 1

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