Algorithm by David Hodges
The following calculation for Easter was written by David Hodges
and is derived by refining the "Butcher's Ecclesiastical Calendar" rule.
The original was written in Visual Basic and can be found at
http://www.gmarts.org/index.php?go=415#EasterHodges
; #FUNCTION# ======================================================================================
; Name...........: _DateEaster
; Description ...: Calculates Easter Sunday for a given year.
; Syntax.........: _DateEaster($iYr)
; Parameters ....: $iYr - The year used to calculate Easter
; Return values .: Success - Easter in the format YYYY/MM/DD
; Failure - Returns an empty string and sets @error = 1
; Author ........: David Hodges, (conversion to AutoIt by czardas)
; Remarks .......: Applies to the revised calculation in the Gregorian calendar from 1583 to 4099 AD
; Example .......; Yes
; ==================================================================================================
Func _DateEaster($iYr)
If StringIsInt($iYr) = 0 Or $iYr < 1583 Or $iYr > 4099 Then Return SetError(1, 0, "")
Local $a, $b, $c, $d, $e, $f, $g, $h, $i, $j, $k, $iDy, $iMth
$a = Int($iYr / 100)
$b = Mod($iYr, 100)
$c = Int(3 * ($a + 25) / 4)
$d = Mod(3 * ($a + 25), 4)
$e = Int(8 * ($a + 11) / 25)
$f = Mod(5 * $a + $b, 19)
$g = Mod((19 * $f + $c - $e), 30)
$h = Int((11 * $g + $f) / 319)
$i = Int((60 * (5 - $d) + $b) / 4)
$j = Mod(60 * (5 - $d) + $b, 4)
$k = Mod(2 * $i - $j - $g + $h, 7)
$iDy = Mod($g - $h + $k + 114, 31) + 1
$iMth = Int(($g - $h + $k + 114) / 31)
If $iDy < 10 Then $iDy = String("0" & $iDy)
Return $iYr & "/0" & $iMth & "/" & $iDy
EndFunc
Example
Save the above code as 'EasterHodges.au3', and then run the code below in SciTE editor.
