Kotlin Programming: The Big Nerd Ranch Guide, First Edition

Formatting a Double

Rather than working with 4.1899999999999995 pieces of gold, you will round the value up to 4.19. String’s format function can be used to round a double to a precision that you define. Update the performPurchase function to format the remaining balance amount:

Listing 8.5  Formatting a double (Tavern.kt)

...
fun performPurchase(price: Double) {
    displayBalance()
    val totalPurse = playerGold + (playerSilver / 100.0)
    println("Total purse: $totalPurse")
    println("Purchasing item for $price")

    val remainingBalance = totalPurse - price
    println("Remaining balance: ${"%.2f".format(remainingBalance)}")
}
...

The gold remaining in the purse is interpolated into the string using $, as you have seen before. But what follows ...