I m trying to convert a long amount in euro cents to a reada

Question

I m trying to convert a long amount in euro cents to a readable value I m not European and I see conflicting information on this Here is my ext func ```fun Long euroCentsToString String val format = NumberFormat getCurrencyInstance format maximumFractionDigits = 2 format currency = Currency getInstance EUR return format format this 100 ``` If I call `849999L euroCentsToString ` I get a result of ` 8 499 00` I thought what I d get is ` 8 499 99` So Basically three issues 1 I thought europeans use ` ` to separate thousands from hundreds 2 I thought europeans use ` ` to designate the start of fractional cents 3 I thought I d see 99 as the cents and not 00

TwoClocks · Answer

My guess is it uses the local e g where you are formatting rules

TwoClocks · Answer

I m pretty sure you can override that

TwoClocks · Answer

TwoClocks · Answer

Also you likely have to specific rounding rules It probably has more than 2 digits after the decimal palce So went you tell it to display just 2 digits it rounds because you didn t tell it otherwise so 999 becomes 00

Colton Idle · Answer

Interesting Yeah if I do val format = NumberFormat getCurrencyInstance Locale Italy for example then I get `8 499 00 ` the trailing euro symbol is interesting but it proves your point

TwoClocks · Answer

what type is `this`

Colton Idle · Answer

It s an extension function so this is referring to the Long

TwoClocks · Answer

It s common to have the symbol after the number in some countries

Colton Idle · Answer

I tried setting RoundingMode Unnecessary but it still seemed to turn the 99 cents into 00

TwoClocks · Answer

oh yeah so if you have 12345 in a long and you divide it by 100 you end up with 123 So when you ask that to be printed with 2 decimal points of resolution it prints out 123 00

Colton Idle · Answer

ah okay so dividing it by 100 is the mistake lemme try that

ephemient · Answer

try BigDecimal+scale

Colton Idle · Answer

Hm Now I end up with 849 999 00 but the original number in cents is 849999

TwoClocks · Answer

so it s expecting a in whole units euros or dollars or whatever and you re giving it a unit in cents

TwoClocks · Answer

so what it s printing out seems correct

Colton Idle · Answer

```return format format this 100 0 ``` fixed it So I needed the 100 0 not 100

TwoClocks · Answer

yeah that s converting it to a float or double before it does the divide

ephemient · Answer

please don t use floating point with currency fixed point will not have any rounding issues

TwoClocks · Answer

I m not sure what your doing but finical system don t use floating point math for currencys

ephemient · Answer

hence my BigDecimal suggestion immediately previously

Colton Idle · Answer

Yeah My BE sends me values in cents

Colton Idle · Answer

so that theres no floating point

Colton Idle · Answer

I didn t know to format it I still needed BigDecimal I m aware of why I would use BigDecimal in other scenarios

Colton Idle · Answer

But turning 599L to a string of $5 99 for example would have never occured to me that I need a BigDecimal

ephemient · Answer

```BigDecimal 599L toBigInteger 2 == BigDecimal 5 99 ``` BigDecimal is exact the scaling is done on powers of 10 it feels like overkill but there isn t another fixed point number type built in

TwoClocks · Answer

You can keep your number in Ints Longs if you like But then you have to do all the prettyPrint stuff by hand mod by 100 to get the cents and print that seperatly to the dollars etc But only the most latency sensitive systems do that And since your printing it you by definition don t care about the latency so just use BigDecimal It s much easier to work with

Colton Idle · Answer

So what < ephemient> posted makes sense but now how do I put that into a number formatter

TwoClocks · Answer

Same way I think number formats will work on a BigDecimal or BigDecimal has it s on formatter I can t rememeber0

ephemient · Answer

```NumberFormat getCurrencyInstance Locale ITALY format BigDecimal 849999L toBigInteger 2 == 8 499 99 NumberFormat getCurrencyInstance Locale forLanguageTag it IT u cu USD format BigDecimal 849999L toBigInteger 2 == 8 499 99 USD NumberFormat getCurrencyInstance Locale forLanguageTag en US u cu EUR format BigDecimal 849999L toBigInteger 2 == 8 499 99 ```

Colton Idle · Answer

It seems like this works Let me know if its bad ```fun Long centsToString String val format = NumberFormat getCurrencyInstance Locale ITALY format maximumFractionDigits = 2 format currency = Currency getInstance EUR return format format BigDecimal this divide BigDecimal 100 0 ```

TwoClocks · Answer

seems fine to me

ephemient · Answer

just use the constructor that lets you set the scale though

Colton Idle · Answer

Makes sense to me The `toBigInteger` was unexpected to me tho

Colton Idle · Answer

```fun Long centsToString String val format = NumberFormat getCurrencyInstance Locale ITALY format currency = Currency getInstance EUR return format format BigDecimal this toBigInteger 2 ``` Ended up with this now

ephemient · Answer

BigDecimal is a wrapper around BigInteger + scale e g where the decimal point is

Colton Idle · Answer

interesting okay Well I have the above extension for now Seems like it ll get the job done and is accurate no weird floating point issues Cheers

ephemient · Answer

I edited my previous example to show that you can embed currency into the locale itself as well