static string?ConvertTrio(int val, int group, bool?femenine)
{
string trio = val.ToString("000");
int cent = CharUtil.ToInt(trio[0]);
int dec = CharUtil.ToInt(trio[1]);
int unit = CharUtil.ToInt(trio[2]);
if (cent == 0 && dec == 0 && unit == 0 && group % 2 == 1)
{
return(null);
}
string?groupName = UnitsGroup(group, unit != 1 || dec > 0 || cent > 0);
string num = CentsDecsUnits(cent, dec, unit, group >= 2 ? null : femenine);
return(" ".Combine(val == 1 && groupName == "mil" ? null : num, groupName));
}