🚀 go-pugleaf

>> Hi, can anybody send me a C function to calculate the Easter of every year?
>> Thanks in advance,
> This is the algorithm Gauss published in 1800 to calculate Easter-date.

[...]

The Gauss algorithm fails to handle certain elements of the algorithm,
and, if I recall correctly, gets A.D. 4200 wrong (it is actually April
20th):

>  a := Year mod 19;
>  b := Year mod 4;
>  c := Year mod 7;
>  k := Year div 100;

a = 1, b = 0, c = 0, k = 42

>  p := k div 3;
>  q := k - k div 4;
>  m := (q - p + 15) mod 30;
>  n := (q + 4) mod 7;
>  d := (19*a + m) mod 30;
>  e := (2*b + 4*c + 6*d + n) mod 7;
>  f := d + e - 9;

p = 14, q = 32, m = 3, n = 1, d = 22, e = 0, f = 13

>  if f <= 0 then
>    begin
>      Month := 3;
>      Day := 31 + f;
>    end
>  else
>    begin
>      Month := 4;
>      if f = 26 then Day := 19
>      else if (f = 25) and (d = 28) then Day := 18
>      else Day := f;
>    end

Gives April 13th, wrong.

-- 
Clive D.W. Feather                       | If you lie to the compiler,
cdwf@cityscape.co.uk   (work, preferred) | it will get its revenge.
clive@stdc.demon.co.uk (home)            |   - Henry Spencer