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Calendar.IsLeapDay Method (Int32, Int32, Int32)

Determines whether the specified date in the current era is a leap day.

Namespace: System.Globalization
Assembly: mscorlib (in mscorlib.dll)

public virtual bool IsLeapDay (
	int year,
	int month,
	int day
)
public boolean IsLeapDay (
	int year, 
	int month, 
	int day
)
public function IsLeapDay (
	year : int, 
	month : int, 
	day : int
) : boolean

Parameters

year

An integer that represents the year.

month

A positive integer that represents the month.

day

A positive integer that represents the day.

Return Value

true if the specified day is a leap day; otherwise, false.

Exception typeCondition

ArgumentOutOfRangeException

year is outside the range supported by the calendar.

-or-

month is outside the range supported by the calendar.

-or-

day is outside the range supported by the calendar.

In order to make up for the difference between the calendar year and the actual time that the earth rotates around the sun or the actual time that the moon rotates around the earth, a leap year has a different number of days than a standard calendar year. Each Calendar implementation defines leap years differently.

A leap day is a day that occurs only in a leap year. For example, in the Gregorian calendar, the 29th day of February is the only leap day.

The following code example compares different implementations of the Calendar class.

using System;
using System.Globalization;


public class SamplesCalendar  {

   public static void Main()  {

      // Creates an instance of every Calendar type.
      Calendar[] myCals = new Calendar[8];
      myCals[0] = new GregorianCalendar();
      myCals[1] = new HebrewCalendar();
      myCals[2] = new HijriCalendar();
      myCals[3] = new JapaneseCalendar();
      myCals[4] = new JulianCalendar();
      myCals[5] = new KoreanCalendar();
      myCals[6] = new TaiwanCalendar();
      myCals[7] = new ThaiBuddhistCalendar();

      // For each calendar, displays the current year, the number of months in that year,
      // and the number of days in each month of that year.
      int i, j, iYear, iMonth, iDay;
      DateTime myDT = DateTime.Today;

      for ( i = 0; i < myCals.Length; i++ )  {
         iYear = myCals[i].GetYear( myDT );
         Console.WriteLine();
         Console.WriteLine( "{0}, Year: {1}", myCals[i].GetType(), myCals[i].GetYear( myDT ) );
         Console.WriteLine( "   MonthsInYear: {0}", myCals[i].GetMonthsInYear( iYear ) );
         Console.WriteLine( "   DaysInYear: {0}", myCals[i].GetDaysInYear( iYear ) );
         Console.WriteLine( "   Days in each month:" );
         Console.Write( "      " );

         for ( j = 1; j <= myCals[i].GetMonthsInYear( iYear ); j++ )
            Console.Write( " {0,-5}", myCals[i].GetDaysInMonth( iYear, j ) );
         Console.WriteLine();

         iMonth = myCals[i].GetMonth( myDT );
         iDay = myCals[i].GetDayOfMonth( myDT );
         Console.WriteLine( "   IsLeapDay:   {0}", myCals[i].IsLeapDay( iYear, iMonth, iDay ) );
         Console.WriteLine( "   IsLeapMonth: {0}", myCals[i].IsLeapMonth( iYear, iMonth ) );
         Console.WriteLine( "   IsLeapYear:  {0}", myCals[i].IsLeapYear( iYear ) );

      }

   }

}


/*
This code produces the following output.  The results vary depending on the date.

System.Globalization.GregorianCalendar, Year: 2002
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.HebrewCalendar, Year: 5763
   MonthsInYear: 13
   DaysInYear: 385
   Days in each month:
       30    30    30    29    30    30    29    30    29    30    29    30    29   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  True

System.Globalization.HijriCalendar, Year: 1423
   MonthsInYear: 12
   DaysInYear: 355
   Days in each month:
       30    29    30    29    30    29    30    29    30    29    30    30   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  True

System.Globalization.JapaneseCalendar, Year: 14
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.JulianCalendar, Year: 2002
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.KoreanCalendar, Year: 4335
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.TaiwanCalendar, Year: 91
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.ThaiBuddhistCalendar, Year: 2545
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

*/

import System.* ;
import System.Globalization.* ;

public class SamplesCalendar
{
    public static void main(String[] args)
    {
        // Creates an instance of every Calendar type.
        Calendar myCals[] = new Calendar[8];
        myCals[0] = new GregorianCalendar() ;
        myCals[1] = new HebrewCalendar();
        myCals[2] = new HijriCalendar();
        myCals[3] = new JapaneseCalendar();
        myCals[4] = new JulianCalendar() ;
        myCals[5] = new KoreanCalendar() ;
        myCals[6] = new TaiwanCalendar() ;
        myCals[7] = new ThaiBuddhistCalendar() ;

        // For each calendar, displays the current year, the number of months
        //  in that year, and the number of days in each month of that year.
        int i, j, iYear, iMonth, iDay;
        DateTime myDT = DateTime.get_Today();

        for(i = 0;i < myCals.length;i++) {
            iYear = myCals[i].GetYear(myDT);
            Console.WriteLine();
            Console.WriteLine("{0}, Year: {1}", 
                System.Convert.ToString(myCals[i].GetType()), 
                System.Convert.ToString(myCals[i].GetYear(myDT)));
            Console.WriteLine("   MonthsInYear: {0}", 
                System.Convert.ToString(myCals [i].GetMonthsInYear(iYear)));
            Console.WriteLine("   DaysInYear: {0}",
                System.Convert.ToString( myCals[i].GetDaysInYear(iYear)));
            Console.WriteLine("   Days in each month:");
            Console.Write("      ");
                
            for(j = 1;j <= myCals[i].GetMonthsInYear(iYear);j++) {
                Console.Write(" {0,-5}", 
                System.Convert.ToString(myCals[i].GetDaysInMonth(iYear, j)));
            } 
            Console.WriteLine();
                
            iMonth = myCals[i].GetMonth(myDT);
            iDay = myCals[i].GetDayOfMonth(myDT);
            Console.WriteLine("   IsLeapDay:   {0}",
            System.Convert.ToString(myCals[i].IsLeapDay(iYear, iMonth, iDay)));
            Console.WriteLine("   IsLeapMonth: {0}", 
                System.Convert.ToString(myCals[i].IsLeapMonth(iYear, iMonth)));
            Console.WriteLine("   IsLeapYear:  {0}", 
                System.Convert.ToString(myCals[i].IsLeapYear(iYear)));
        }  
    } //main
} //SamplesCalendar
 
/*
System.Globalization.GregorianCalendar, Year: 2004
   MonthsInYear: 12
   DaysInYear: 366
   Days in each month:
       31    29    31    30    31    30    31    31    30    31    30    31
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  True

System.Globalization.HebrewCalendar, Year: 5764
   MonthsInYear: 12
   DaysInYear: 355
   Days in each month:
       30    30    30    29    30    29    30    29    30    29    30    29
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.HijriCalendar, Year: 1425
   MonthsInYear: 12
   DaysInYear: 354
   Days in each month:
       30    29    30    29    30    29    30    29    30    29    30    29
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.JapaneseCalendar, Year: 16
   MonthsInYear: 12
   DaysInYear: 366
   Days in each month:
       31    29    31    30    31    30    31    31    30    31    30    31
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  True

System.Globalization.JulianCalendar, Year: 2004
   MonthsInYear: 12
   DaysInYear: 366
   Days in each month:
       31    29    31    30    31    30    31    31    30    31    30    31
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  True

System.Globalization.KoreanCalendar, Year: 4337
   MonthsInYear: 12
   DaysInYear: 366
   Days in each month:
       31    29    31    30    31    30    31    31    30    31    30    31
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  True

System.Globalization.TaiwanCalendar, Year: 93
   MonthsInYear: 12
   DaysInYear: 366
   Days in each month:
       31    29    31    30    31    30    31    31    30    31    30    31
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  True

System.Globalization.ThaiBuddhistCalendar, Year: 2547
   MonthsInYear: 12
   DaysInYear: 366
   Days in each month:
       31    29    31    30    31    30    31    31    30    31    30    31
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  True
 */

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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