NumberInWords

A program that can be reused to convert numbers into words.

An API defined in NumberInWordsService interface: String numberInWords(int num)

which is the essence and translates a number into words.
The implementations of this API are configurable and provides a choice of
1. Metric number system and
2. Indian number system

The metric system uses the common use of expressing in terms of
billions, millions thousands etc
The Indian system uses the terms lakh and crore and expresses the numbers therein.
Eg:
Metric
20,344,510 ->twenty million three hundred and forty four thousand five hundred and ten
Indian
2,03,44,510 ->two crore three lakh forty four thousand five hundred and ten