Calendar.IsLeapYear Method

Definition

Namespace:

System.Globalization

Assembly:

System.Runtime.dll

When overridden in a derived class, determines whether a year is a leap year.

Overloads

IsLeapYear(Int32)	Determines whether the specified year in the current era is a leap year.
IsLeapYear(Int32, Int32)	When overridden in a derived class, determines whether the specified year in the specified era is a leap year.

IsLeapYear(Int32)

Source:

Calendar.cs

Determines whether the specified year in the current era is a leap year.

public:
 virtual bool IsLeapYear(int year);

public virtual bool IsLeapYear (int year);

abstract member IsLeapYear : int -> bool
override this.IsLeapYear : int -> bool

Public Overridable Function IsLeapYear (year As Integer) As Boolean

Parameters

year

Int32

An integer that represents the year.

Returns

Boolean

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

Exceptions

ArgumentOutOfRangeException

year is outside the range supported by the calendar.

Examples

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

using namespace System;
using namespace System::Globalization;
int main()
{
   
   // Creates an instance of every Calendar type.
   array<Calendar^>^myCals = gcnew array<Calendar^>(8);
   myCals[ 0 ] = gcnew GregorianCalendar;
   myCals[ 1 ] = gcnew HebrewCalendar;
   myCals[ 2 ] = gcnew HijriCalendar;
   myCals[ 3 ] = gcnew JapaneseCalendar;
   myCals[ 4 ] = gcnew JulianCalendar;
   myCals[ 5 ] = gcnew KoreanCalendar;
   myCals[ 6 ] = gcnew TaiwanCalendar;
   myCals[ 7 ] = gcnew 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;
   int j;
   int iYear;
   int iMonth;
   int 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

*/

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

*/

Imports System.Globalization


Public Class SamplesCalendar   

   Public Shared Sub Main()

      ' Creates an instance of every Calendar type.
      Dim myCals(7) As Calendar
      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.
      Dim i, j, iYear, iMonth, iDay As Integer
      Dim myDT As DateTime = DateTime.Today

      For i = 0 To myCals.Length - 1
         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 To myCals(i).GetMonthsInYear(iYear)
            Console.Write(" {0,-5}", myCals(i).GetDaysInMonth(iYear, j))
         Next 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))
      Next i 

   End Sub

End Class


'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

Remarks

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 from a standard calendar year. Each Calendar implementation defines leap years differently.

See also

• IsLeapMonth(Int32, Int32)
• IsLeapDay(Int32, Int32, Int32)

IsLeapYear(Int32, Int32)

Source:

Calendar.cs

When overridden in a derived class, determines whether the specified year in the specified era is a leap year.

public:
 abstract bool IsLeapYear(int year, int era);

public abstract bool IsLeapYear (int year, int era);

abstract member IsLeapYear : int * int -> bool

Public MustOverride Function IsLeapYear (year As Integer, era As Integer) As Boolean

Parameters

year

Int32

An integer that represents the year.

era

Int32

An integer that represents the era.

Returns

Boolean

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

Exceptions

ArgumentOutOfRangeException

year is outside the range supported by the calendar.

-or-

era is outside the range supported by the calendar.

Remarks

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 from a standard calendar year. Each Calendar implementation defines leap years differently.

Notes to Implementers

The derived class must support CurrentEra when it is passed as the era parameter. One way to support CurrentEra is by replacing it with the value stored in Eras[0], which is the value for the current era of the calendar.

See also

• CurrentEra
• Eras
• IsLeapMonth(Int32, Int32)
• IsLeapDay(Int32, Int32, Int32)