fpc/packages/amunits/examples/easter.pas
marco 88851f7852 * amunits moved
git-svn-id: trunk@10043 -
2008-01-27 13:16:04 +00:00

77 lines
1.4 KiB
ObjectPascal

Program easter;
{
easter v1.0
© 1995 by Andreas Tetzl
FREEWARE
This is a little program to calculate the date of
easter for years between 1583 and 2299.
Start it in a shell with the year as argument.
}
{
Translated to fpc pascal.
21 Mar 2001.
nils.sjoholm@mailbox.swipnet.se
}
uses amigados;
const version : pchar = '$VER: easter v1.0 (3-Nov-95) by Andreas Tetzl';
VAR i,a,b,c,d,e,m,n : Integer;
year, month, day : longint;
BEGIN
if (ParamStr(1) = '?') or (ParamStr(1) = '') then
BEGIN
Writeln('YEAR/N');
halt(20);
END;
i:=StrToLong(ParamStr(1),year);
if (year<1583) or (year>2299) then
BEGIN
Writeln('only years between 1583 and 2299 allowed');
halt(20);
END;
Case year of
1583..1699 : BEGIN m:=22; n:=2; END;
1700..1799 : BEGIN m:=23; n:=3; END;
1800..1899 : BEGIN m:=23; n:=4; END;
1900..2099 : BEGIN m:=24; n:=5; END;
2100..2199 : BEGIN m:=24; n:=6; END;
2200..2299 : BEGIN m:=25; n:=0; END;
end;
a:=year mod 19;
b:=year mod 4;
c:=year mod 7;
d:=(19*a+m) mod 30;
e:=(2*b+4*c+6*d+n) mod 7;
day:=22+d+e;
if day<=31 then
month:=3
else
BEGIN
month:=4;
day:=d+e-9;
END;
if (month=4) and (day=26) then day:=19;
if (month=4) and (day=25) and (d=28) and (e=6) and (a>10) then day:=18;
Write(year,'-');
if month=3 then Write('Mar') else Write('Apr');
Writeln('-',day);
END.