Question

Hi I have a Start Date and End Date per record in a db.

I need to check to see where the time period falls in a 2 year period broken into two lots of quarters then display what quarters each record falls into.

Quarter 1 includes June 09, Jul 09, Aug 09
Quarter 2 includes Sept 09, Oct 09, Nov 09
Quarter 3 includes Dec 09, Jan 10, Feb 10
Quarter 4 includes Mar 10, Apr 10, May 10
Quaretr 5 includes Jun 10, Jul 10…

e.g. 01/10/09 – 01/06/10 would fall into quarters 2, 3, 4 & 5

I am very new to .NET so any examples would be much appreciated.

Answer 1

You would call IntervalInQuarters as follows:

IntervalInQuarters(new DateTime(2007, 10, 10), new DateTime(2009, 10, 11));

The function returns a list of quarter start dates. Note that the range of quarters searched is defined within the function itself. Please edit as appropriate for your situation. They key point is to make sure the interval/quarter intersection logic is right.

private List<DateTime> IntervalInQuarters(DateTime myStartDate, DateTime myEndDate)
{
    DateTime quarterStart = new DateTime(2006, 06, 01);
    DateTime nextQuarterStart = new DateTime(2006, 09, 01);
    DateTime finalDate = new DateTime(2011, 01, 01);
    List<DateTime> foundQuarters = new List<DateTime>();

    while (quarterStart < finalDate)
    {
        // quarter intersects interval if:
        // its start/end date is within our interval
        // our start/end date is within quarter interval
        DateTime quarterEnd = nextQuarterStart.AddDays(-1);
        if (DateInInterval(myStartDate, quarterStart, quarterEnd) ||
            DateInInterval(myEndDate, quarterStart, quarterEnd) ||
            DateInInterval(quarterStart, myStartDate, myEndDate) ||
            DateInInterval(quarterEnd, myStartDate, myEndDate))
        {
            foundQuarters.Add(quarterStart);
        }

        quarterStart = nextQuarterStart;
        nextQuarterStart = nextQuarterStart.AddMonths(3);
    }

    return foundQuarters;
}

private bool DateInInterval(DateTime myDate, DateTime intStart, DateTime intEnd)
{
    return ((intStart <= myDate) && (myDate <= intEnd));
}