private bool IsDateValid(string cpr)
{
var day = int.Parse(cpr.Substring(0, 2));
var month = int.Parse(cpr.Substring(2, 2));
var yearEnding = int.Parse(cpr.Substring(4, 2));
var serialNumber = int.Parse(cpr.Substring(6, 1));
var year = _serialNumberParser.Parse(yearEnding, serialNumber);
return(day > 0 && day <= DateTime.DaysInMonth(year, month));
}
//Extracting Birthdate from CPR number
public DateTime GetBirthDate(string cpr)
{
var trimmedCpr = Parse(cpr);
if (string.IsNullOrEmpty(trimmedCpr))
{
throw new ArgumentException("The cpr number was invalid", nameof(cpr));
}
var day = int.Parse(cpr.Substring(0, 2));
var month = int.Parse(cpr.Substring(2, 2));
var yearEnding = int.Parse(cpr.Substring(4, 2));
var serialNumber = int.Parse(cpr.Substring(6, 1));
var birthYear = _serialParser.Parse(yearEnding, serialNumber);
return(new DateTime(birthYear, month, day));
}