Number Write

Given a positive number integer, compute the written text for the number. Number can be from 0 - 10,000,000,000,000 (10 trillion)

Approach

First step is to be able to break up 3 digits at a time into its individual digits. By using the helper function "ThousandWriter" it will write out the text for each 3-digit increment. I then proceed breaking down the problem recursively by concatenate per thousand.

##Induction ####Base cases

1. Number=0,Level=0 -> return "Zero"
2. Number=0 -> return ""

####Inductive Step Append the current string from "ThousandWriter" to the result of the recursion.

Results

Below are some results:

1361992721 : One Billion Three Hundred Sixty One Million Nine Hundred Ninety Two Thousand Seven Hundred Twenty One

113492884 : One Hundred Thirteen Million Four Hundred Ninety Two Thousand Eight Hundred Eighty Four

437334182 : Four Hundred Thirty Seven Million Three Hundred Thirty Four Thousand One Hundred Eighty Two