Calculate the date of Easter Sunday

Question

Write a program to compute the date of Easter Sunday. Easter Sunday is the first Sunday after the first full moon of spring. Use the algorithm invented by the mathematician

Answer 1

VisualBasic Excel VBA Code

Function Easter_Sunday(Year)
    k = Int(Year / 100)                                         'the secular number
    s = 2 - Int((3 * k + 3) / 4)                                'the secular sun control
    m = 15 + Int((3 * k + 3) / 4) - Int((8 * k + 13) / 25)      'the secular moon circuit
    a = Year Mod 19                                             'the lunar parameter
    d = (19 * a + m) Mod 30                                     'the seed for the first full moon in spring
    r = Int(d / 29) + (Int(d / 28) - Int(d / 29)) * Int(a / 11) 'the calendar correction amount
    EB = 21 + d - r                                             'the Easter border
    FS = 7 - (Year + Int(Year / 4) + s) Mod 7                   'the first Sunday in March
    ED = 7 - (EB - FS) Mod 7                                    'Easter distance in days
    ESM = EB + ED - 1                                           'the date of Easter Sunday as the March date

    '--------------------------------------- "For Years (1900-9999)" ------------------------------
    Easter_Sunday = DateValue(1 & "." & 3 & "." & Year) + ESM

    '--------------------------------------- "or for all Years" -----------------------------------
    Month_ = 3 + Int(ESM / 31)               'Month March or April
    ES = 1 + ESM Mod 31                      'Eastersunday

    Easter_Sunday = ("Su, " & Year & "." & Format(Month_, "00") & "." & Format(ES, "00"))

End Function