LESSON 163 OF 414 · PROJECTS: EVERYDAY PROGRAMS

Shopping Cart V2 - Tax and Discount in Kotlin

Practice

Add a discount and sales tax to a single-item purchase using integer math.

You start with:

        val item = "Coffee Mug"
        val price = 12
        val quantity = 3
        val taxRate = 8
        val discount = 5

Build:

Subtotal: $36
Discount: $5
Tax: $2
Total: $33

Rules:

subtotal = price * quantity.
afterDiscount = subtotal - discount (the discount is a flat amount taken off before tax).
tax = afterDiscount * taxRate / 100 (integer division, so the result is rounded down). The tax is charged on the discounted amount.
total = afterDiscount + tax.
Build four lines (Subtotal, Discount, Tax, Total) and join them with a newline "\n" into one string result, then print it with println(result).

Compute the four numbers (subtotal, afterDiscount, tax, total) before formatting.

In Kotlin "Total: $" + total converts the number to text for you.

Kotlin's Int / Int truncates, so afterDiscount * taxRate / 100 already rounds down.

        val item = "Coffee Mug"
        val price = 12
        val quantity = 3
        val taxRate = 8
        val discount = 5

        val subtotal = price * quantity
        val afterDiscount = subtotal - discount
        val tax = afterDiscount * taxRate / 100
        val total = afterDiscount + tax
        val line1 = "Subtotal: $" + subtotal
        val line2 = "Discount: $" + discount
        val line3 = "Tax: $" + tax
        val line4 = "Total: $" + total
        val result = line1 + "\n" + line2 + "\n" + line3 + "\n" + line4
        println(result)

STEP 1 OF 10

Guided

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Shopping Cart V2 - Tax and Discount in Kotlin

Shopping Cart V2 in Kotlin