Why do I feel like google search is getting worse....

# getting-started

[Colton Idle]

Why do I feel like google search is getting worse. lol. How do I write the following formatter in kotlin?
I have Int cents and I want to just convert it to a price. e.g. 100 cents == $1.00, and 99 cents $0.99 and 100000 would be $1,000.00

[Ronny Bräunlich]

Have you tried java.text.NumberFormat?

[Colton Idle]

I currently have this

val dollars = price / 100
val remainingCents = price % 100
val df = DecimalFormat("#,##0.00", DecimalFormatSymbols(Locale.US))

return "$${df.format(dollars + remainingCents / 100.0)}"

[Colton Idle]

seems to work. But don't know if I'm missing something else basic. or if that's just what it is? 🤷

[Ronny Bräunlich]

Depending on the precision you need but in case a Double is enough you can do it like this:

val cents = 99 / 100.0
val currencyInstance = NumberFormat.getCurrencyInstance(<http://Locale.US|Locale.US>)
println(currencyInstance.format(cents))

Apart from this your solution looks fine to me

[Arjan van Wieringen]

Using floating point numbers for money is not a good idea. Use decimal number formats for this

[ascii]

Yep, to avoid rounding errors it's better to use non-float number formats.

For example, a simple comparison like this:

val left = 0.5f + 0.1f;
val right = 0.7f - 0.1f;
println("$left, $right, ${left == right}")

will print 0.6, 0.59999996, false.

[Ruckus]

Using floating point values in money calculations is bad. Using them for display formatting isn't.

[Robert Williams]

*as long as the numbers you're displaying aren't really big; things start to fall apart around $10^14 but at this point you probably won't miss a few cents blob wink

[ephemient]

val cents = 99.toBigDecimal().scaleByPowerOfTen(-2)
NumberFormat.getCurrencyInstance(<http://Locale.US|Locale.US>).format(cents)

also works with no potential rounding (JVM only of course)

[Colton Idle]

I feel like there's a lot of options here. But in general, im aware that floating points and money is just asking for trouble. i figured in this scenario it wouldn't be too bad since i have cents as an Int. ephemient answer looks pretty smooth though. ill try that.

[Colton Idle]

Nice. swapped in that impl and all my tests pass. no more "#,##0.00", needed. thanks all