eng-numbers.nim

const teens = @[
    "zero", "one", "two", "three", "four",
    "five", "six", "seven", "eight", "nine",
    "ten", "eleven", "twelve", "thirteen", "fourteen",
    "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"]
const tens = @[
    "zeroty", "onety", "twenty", "thirty", "fourty",
    "fifty", "sixty", "seventy", "eighty", "ninety"]
const hundred = "hundred"
const anudo = "and"
const thousand = @["thousand", "thousands"]

proc toEngNum(n: int): string =
    let thousands = n div 1000
    if thousands > 0:
        let
            rem = n mod 1000
            rest = if rem > 0: " " & toEngNum(rem)
                         else: ""
            r = thousand[min(thousands - 1, 1)]
        return toEngNum(thousands) & " " & r & rest
    let hundreds = (n div 100) mod 10
    if hundreds > 0:
        let
            rem = n mod 100
            rest = if rem > 0: " " & anudo & " " & toEngNum(rem)
                         else: ""
        return toEngNum(hundreds) & " " & hundred & rest

    if n >= 20:
        let
            rem = n mod 10
            rest = if rem > 0: "-" & toEngNum(rem)
                         else: ""
        return tens[n div 10] & rest

    return teens[n]