import re, strutils, terminal, random

proc addCommas*(num: int) =
  # strfmt complains about comma?!
  let s = ($num).replace (re"(\d)(?=(\d{3})+(?!\d))", r"1,")
  let backToNum = parseInt(s.replace(","))
  let color = if num == backToNum: fgGreen else: fgRed
  stdout.setForegroundColor color, false
  echo num, " =addCommas=> ", s, " =parseInt=> ", backToNum

randomize()
for i in 1..100:
  addCommas(random(1000000))