Determining the number of decimal numbers for a currency

Question

On the iPhone:

Using the US locale, a currency looks like this: $1,234.56
Using the UK locale, a currency looks like this: £1,234.56
Using the German (Germany) locale, a currency looks like this: 1.234,56 €

and finally, a Japanese currency: ¥1,234

The Japanese currency has no decimals and this impacts my custom keyboard significantly. I'm trying to find a method in the Cocoa-touch framework which will tell me how many decimal places a specific currency has - my hard-coded value of 2 isn't doing me justice :(

Can anyone help?

Answer 1

Financial companies maintain databases of this kind of information. You might be able to buy the data or import it from an online source.

Note also: some currencies need three or four decimal places. See http://www.londonfx.co.uk/ccylist.html for examples.

Answer 2

I haven't programmed in Cocoa for ages, but from the documentation for NSNumberFormatter, there's a function called 'currencyDecimalSeparator' - that might at least tell you if a currency has one at all, which might be a start?

Answer 3

You should be able to use the CFNumberFormatter objects to get the information you need. Specifically you could use CFNumberFormatterGetDecimalInfoForCurrencyCode:

CFStringRef localeIdent = CFSTR("JPY");

int numDecimals;
double rounding;
BOOL result = CFNumberFormatterGetDecimalInfoForCurrencyCode(localeIdent, &numDecimals, &rounding);

I hope that helps.