Could someone explain to me why this happens?

Question

This code works, but I couldn't finishing this exam because the Output are suppose (0.0), but they are give me this (0.0, Kotlin.Unit )-Output. So I don't know way the system prints Kotlin.Unit ?

Code: https://code.sololearn.com/cqzxiu9SZz6d

Input:
99.8
false

fun shippingCost(amount: Double, inter: Boolean) {
if(amount < 75.0 && !inter) { println((10.0 * amount) / 100.0) }

else if (inter) {
var num = (15.0 * amount / 100.0)
if (num > 50.0) { num = 50.0 }
println(num )
}

else if ( amount > 75.0 && !inter) { println(0.0) }
}

// inter significa international
fun main(args: Array<String>) {
val total = readLine()!!.toDouble()
val inter = readLine()!!.toBoolean()
println(shippingCost(total, inter))
}

Answer 1

O wohw, you code works, and you wrote it super nice and legible🪶, I loved it, I'm going to read it and re-read it to learn to write like that, I really loved it, thank you very much for your kind help🙏🏻.

Answer 2

You killing me 🤣, I'm using this (10.0 * amount) / 100.0), and jut super simple -> amount * 0.1. 🤣, thank you I'm learn so much with you code TY🙏🏻

Answer 3

I'm ready try this solution first, but the sistem geve me another error in the last key, and I do not know way? For that I'm trying with the println.