Day Of Year

This algorithm finds the number of current day in a year according to the input date.

• C#
• VB.Net
• C
• C++
• PHP

									Public Shared Function DayOfYear(year As UInteger, month As Byte, day As Byte) As Integer
	Dim days As UShort() = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334}

	If IsLeapYear(year) AndAlso month >= 2 Then
		Return days(month - 1) + day + 1
	End If

	Return days(month - 1) + day
End Function

Private Shared Function IsLeapYear(year As UInteger) As Boolean
	Return (year Mod 4 = 0 AndAlso (year Mod 100 <> 0 OrElse year Mod 400 = 0))
End Function
								

Example

									Dim value = DayOfYear(CUInt(DateTime.Now.Year), CByte(DateTime.Now.Month), CByte(DateTime.Now.Day))
								

Output

									271