Question

I use this code from another question:

private bool NthDayOfMonth(DateTime date, DayOfWeek dow, int n){
  int d = date.Day;
  return date.DayOfWeek == dow && (d-1)/7 == (n-1);
}

It works fine. But it not checks a last day ( for me it’s when n = 5). How to modify it?
Thanks.

Answer 1

The method below checks the given date is the last date of week of month.

private bool IsLastOfMonth(DateTime date)
{
    var oneWeekAfter = date.AddDays(7);
    return oneWeekAfter.Month != date.Month;
}

So there is new method, it just checks mondays

private bool IsLastMonday(DateTime date)
{
    if (date.DayOfWeek != DayOfWeek.Monday) 
        return false; // it is not monday

    // the next monday is...
    var oneWeekAfter = date.AddDays(7);

    // and is it in same month?, if it is, that means its not last monday
    return oneWeekAfter.Month != date.Month;
}