strings at index 0 and 1 are not used , they is to make array indexing simple
string ten [ ] = { " " , " " , " twenty ▁ " , " thirty ▁ " , " forty ▁ " , " fifty ▁ " , " sixty ▁ " , " seventy ▁ " , " eighty ▁ " , " ninety ▁ " } ;