Calculate the number of weekdays between two dates in C#

by

O(1) solution:

// Count days from d0 to d1 inclusive, excluding weekends
public static int countWeekDays(DateTime d0, DateTime d1)
{
    int ndays = 1 + Convert.ToInt32((d1 - d0).TotalDays);
    int nsaturdays = (ndays + Convert.ToInt32(d0.DayOfWeek)) / 7;
    return ndays - 2 * nsaturdays
           - (d0.DayOfWeek == DayOfWeek.Sunday ? 1 : 0)
           + (d1.DayOfWeek == DayOfWeek.Saturday ? 1 : 0);
}

Examples for January 2014:

    January 2014
Su Mo Tu We Th Fr Sa
          1  2  3  4
 5  6  7  8  9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31

countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 1)); // 1
countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 2)); // 2
countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 3)); // 3
countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 4)); // 3
countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 5)); // 3
countWeekDays(new DateTime(2014, 1, 1), new DateTime(2014, 1, 6)); // 4

N.B. The DateTime inputs should be at around the same time of the day. If you are creating DateTime objects based solely on year, month, and day as in the examples above, then you should be fine. As a counter example, 12:01am on Jan 1 to 11:59pm Jan 2 spans only 2 days, but the above function will count 3 if you use those times.

More Related Contents:

  1. Return array from function.
  2. Reading/writing an INI file
  3. Getting ServiceStack to retain type information
  4. Move GameObject over time
  5. Copy file(s) from one project to another using post build event…VS2010
  6. Converting BitmapImage to Bitmap and vice versa
  7. Serialize dictionary as array (of key value pairs)
  8. C# optional parameters on overridden methods
  9. Getting day suffix when using DateTime.ToString()
  10. JSON string to CSV and CSV to JSON conversion in c#
  11. C# equivalent of DllMain in C (WinAPI)
  12. How do I create a message box with “Yes”, “No” choices and a DialogResult?
  13. “const correctness” in C#
  14. How to get some values from a JSON string in C#?
  15. Create object instance without invoking constructor?
  16. Can you compile C# so it doesn’t need the .NET Framework at runtime?
  17. Can a DbContext enforce a filter policy?
  18. Extension method on enumeration, not instance of enumeration
  19. Enter key pressed event handler
  20. How to send email to multiple address using System.Net.Mail
  21. WebClient accessing page with credentials
  22. Is there any generic Parse() function that will convert a string to any type using parse?
  23. WPF window from a Console project?
  24. How do I use a Service Account to Access the Google Analytics API V3 with .NET C#?
  25. Why in unity i’m getting the warning: You are trying to create a MonoBehaviour using the ‘new’ keyword? [closed]
  26. Implementations of interface through Reflection
  27. Prism assembly reference failure: System.Windows.Interactivity
  28. “Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))”
  29. C#/WPF: Disable Text-Wrap of RichTextBox
  30. WPF + MVVM + RadioButton : How to handle binding with single property?

Leave a Comment