Count of quarter between dates

I want to calculate the count of total quarters (of a year) in the given time span开发者_运维技巧.

for example:

start date = 1-june -2009
end date = 18-july-2011

count should be = 10.

one more 
start date = 4-Jan-2009 
end date = 27-oct -2010
count =8.

I have not been able to get the correct result.

---

Your example is wrong: there are only 7 quarters between 4-Jan-2009 and 27-oct -2010

You could simply add a reference to the Microsoft.VisualBasic.dll to your project and use DateDiff:

VB:

Public Shared Function getQuartersBetween(ByVal d1 As Date, ByVal d2 As Date) As Int32
    Return DateDiff(DateInterval.Quarter, d1, d2)
End Function

C#:

public static int getQuartersBetween(System.DateTime d1, System.DateTime d2)
{
    return Microsoft.VisualBasic.DateAndTime.DateDiff(DateInterval.Quarter, d1, d2);
}

or you could write your own implementation:

public class Quarter
{

    public static long GetQuarters(DateTime dt1, DateTime dt2) 
    { 
        double d1Quarter = GetQuarter(dt1.Month); 
        double d2Quarter = GetQuarter(dt2.Month); 
        double d1 = d2Quarter - d1Quarter; 
        double d2 = (4 * (dt2.Year - dt1.Year)); 
        return Round(d1 + d2); 
    } 

    private static int GetQuarter(int nMonth) 
    { 
        if (nMonth <= 3) 
            return 1; 
        if (nMonth <= 6) 
            return 2; 
        if (nMonth <= 9) 
            return 3; 
        return 4; 
    } 

    private static long Round(double dVal) 
    { 
        if (dVal >= 0) 
              return (long)Math.Floor(dVal); 
        return (long)Math.Ceiling(dVal); 
    } 
}

or in VB.NET:

Public Class Quarter

    Public Shared Function GetQuarters(ByVal dt1 As DateTime, ByVal dt2 As DateTime) As Long
        Dim d1Quarter As Double = GetQuarter(dt1.Month)
        Dim d2Quarter As Double = GetQuarter(dt2.Month)
        Dim d1 As Double = d2Quarter - d1Quarter
        Dim d2 As Double = (4 * (dt2.Year - dt1.Year))
        Return Round(d1 + d2)
    End Function

    Private Shared Function GetQuarter(ByVal nMonth As Integer) As Integer
        If nMonth <= 3 Then
            Return 1
        End If
        If nMonth <= 6 Then
            Return 2
        End If
        If nMonth <= 9 Then
            Return 3
        End If
        Return 4
    End Function

    Private Shared Function Round(ByVal dVal As Double) As Long
        If dVal >= 0 Then
            Return CLng(Math.Floor(dVal))
        End If
        Return CLng(Math.Ceiling(dVal))
    End Function

End Class

---

Code for you : Try below code

 public static void Main()
    {
        //Application.Run(new XmlTreeDisplay());
        int monthdiuff = monthDifference(Convert.ToDateTime("01/04/09"), Convert.ToDateTime("10/27/10"));
        Console.WriteLine(monthdiuff);
        int totalQuater = (monthdiuff / 3) + (monthdiuff%3);
        Console.WriteLine(totalQuater);
        Console.ReadLine();
    }

    private static int monthDifference(DateTime startDate, DateTime endDate)
    {
        int monthsApart = 12 * (startDate.Year - endDate.Year) + startDate.Month - endDate.Month;
        return Math.Abs(monthsApart);
    }

---

Without some code to look over I can't help you find your exact problem.

If it were me I would probably find the difference between the dates in days, then divide by number of days in a quarter (91 or so). I'm sure that C# has some kind of date parsing module that can read in the dates as a string, giving you two objects that you could then subtract to find the difference in days.

---

This is one crude form of calculating the quarters based on your assumptions, you can choose to modify as it is it works good enough

DateTime dt1 = new DateTime(2009, 1, 1);// new DateTime(2009, 6, 1);
DateTime dt2 = new DateTime(2010, 10, 27);// new DateTime(2011, 7, 18);
if (dt1.Month < 4)
  dt1 = new DateTime(dt1.Year,1,1);
else if (dt1.Month < 7)
  dt1 = new DateTime(dt1.Year,4,1);
else if (dt1.Month < 10)
  dt1 = new DateTime(dt1.Year,7,1);
else
  dt1 = new DateTime(dt1.Year,10,1);
if (dt2.Month < 4)
   dt2 = new DateTime(dt2.Year, 3, DateTime.DaysInMonth(dt2.Year, 3)); 
else if (dt2.Month < 7)
   dt2 = new DateTime(dt2.Year, 6, DateTime.DaysInMonth(dt2.Year, 6));
else if (dt2.Month < 10)
   dt2 = new DateTime(dt2.Year, 9, DateTime.DaysInMonth(dt2.Year, 9));
else
   dt2 = new DateTime(dt2.Year, 12, DateTime.DaysInMonth(dt2.Year, 12));

TimeSpan ts = dt2 - dt1;
int quarters = (int) ts.TotalDays/90;
Console.WriteLine(quarters);

I am baselining the dates to the start and end of the quarters as you want and then assuming for 90 day quarter transforming the diff as int. Works for your mentioned examples,see if it suits you well enough

---

If the definition of a quarter is a 90-day difference, it's easy of course:

    internal static int GetNumberOfQuarters(DateTime p_DtStart, DateTime p_DtEnd)
    {
        TimeSpan span = p_DtEnd.Subtract(p_DtStart);
        return (int)span.TotalDays % 90;
    }

But that's not what you're looking for. What about this (not tested but you'll get the idea)

internal static class DateTimeTools
{
    internal static int GetNumberOfQuartersBetweenDates(DateTime startDate, DateTime endDate)
    {
        int iYearStart, iYearEnd, iMonthStart, iMonthEnd, iDayStart, iDayEnd;
        iYearStart = startDate.Year;
        iYearEnd = endDate.Year;
        iMonthStart = startDate.Month;
        iMonthEnd = endDate.Month;
        iDayStart = startDate.Day;
        iDayEnd = endDate.Day;

        int iYearDiff, iQuarterDiff, iDayDiff;
        iYearDiff = iYearEnd - iYearStart;
        iQuarterDiff = iMonthEnd % 3 - iMonthStart % 3;
        iDayDiff = iDayEnd - iDayStart;

        int iNumOfQuarters = 0;

        // at least a year difference? 
        if ((iYearDiff > 0 && iQuarterDiff > 0) || iYearDiff > 0 && iQuarterDiff == 0 && iDayDiff >= 0)
        {
            iNumOfQuarters = iYearDiff * 4 + iQuarterDiff;
        }
        // at least a quarter difference?
        // within different years
        if ((iYearDiff > 0 && iQuarterDiff <= 0)) // eg, dec 2010 - feb 2011 iYearDiff 1 iQuarterDiff -3
        {
            if ((iQuarterDiff == -3 && iDayDiff >= 0) || iQuarterDiff > -3)
            {
                iNumOfQuarters = iQuarterDiff + 4;
            }
        }
        // within the same year
        if (iYearDiff == 0 && iQuarterDiff > 0)
        {
            if ((iQuarterDiff == 1 && iDayDiff >= 0) || iQuarterDiff > 1)
            {
                iNumOfQuarters = iQuarterDiff;
            }
        }
        return iNumOfQuarters;
    }
}

Regards, Nico

---

public static string GetQuarter(this DateTime date)
        {
            var quarterList = new List<string>();

            if (date.Month >= 1 && date.Month <= 3)
                return "Q1";
            else if (date.Month >= 4 && date.Month <= 6)
                return "Q1,Q2";
            else if (date.Month >= 7 && date.Month <= 9)
                return "Q1,Q2,Q3";
            else
                return "Q1,Q2,Q3,Q4";
        }

This too can be used as an extension method if you are expecting to get a list of Quarters, You can later on use GetQuarter().Split(new[] { ',' }).Count() to get the count.

---

Easy formula to get quarters difference:

{
    int firstQuarter = getQuarter(first);
    int secondQuarter = getQuarter(second);
    return 1 + Math.Abs(firstQuarter - secondQuarter);
}

private static int getQuarter(DateTime date)
{
    return (date.Year * 4) + ((date.Month - 1) / 3);
}