```Contributor: ROBERT WOOSTER

(*     JULIAN.PAS - test Julian algorithms

test values: 1/1/79 = 2443875
1/1/1900 = 2415021
1/1/70 = 2440588
8/28/40 = 2429870

Robert B. Wooster [72415,1602]
March 1985

Note: because of the magnitude of the numbers involved
here this probably requires an 8x87 and hence is limited
to MS or PC/DOS machines.  However, it may work with the
forthcoming BCD routines.
*)

program JULIAN;

var
JNUM     : real;
month,
day,
year     : integer;

{----------------------------------------------}
function Jul( mo, da, yr: integer): real;
{ this is an implementation of the FORTRAN one-liner:
JD(I, J, K) = K - 32075 + 1461 * (I + 4800 + (J-14) / 12) / 4
+ 367 * (j - 2 - ((J - 14) / 12) * 12) / 12
- 3 * (( I + 4900 + (J - 14) / 12) / 100 / 4; where I,J,K are
year, month, and day.  The original version takes advantage of
FORTRAN's automatic truncation of integers but requires support
of integers somewhat larger than Turbo's Maxint, hence all of the
Int()'s .  The variable returned is an integer day count using
1 January 1980 as 0. }

var     i, j, k, j2, ju: real;
begin
i := yr;     j := mo;     k := da;
j2 := int( (j - 14)/12 );
ju := k - 32075 + int(1461 * ( i + 4800 + j2 ) / 4 );
ju := ju + int( 367 * (j - 2 - j2 * 12) / 12);
ju := ju - int(3 * int( (i + 4900 + j2) / 100) / 4);
Jul := ju;
end;  { Jul }

{----------------------------------------------}
procedure JtoD(pj: real; var mo, da, yr: integer);
{ this reverses the calculation in Jul, returning the
result in a Date_Rec }
var     ju, i, j, k, l, n: real;
begin
ju := pj;
l := ju + 68569.0;
n := int( 4 * l / 146097.0);
l := l - int( (146097.0 * n + 3)/ 4 );
i := int( 4000.0 * (l+1)/1461001.0);
l := l - int(1461.0*i/4.0) + 31.0;
j := int( 80 * l/2447.0);
k := l - int( 2447.0 * j / 80.0);
l := int(j/11);
j := j+2-12*l;
i := 100*(n - 49) + i + l;
yr := trunc(i);
mo := trunc(j);
da := trunc(k);
end;  { JtoD }

{-----------------MAIN-----------------------------}
begin
writeln('This program tests the Julian date algorithms.');
writeln('Enter a calendar date in the form MM DD YYYY ');
writeln('Enter a date of 00 00 00 to end the program.');

day := 1;
while day<>0 do begin

writeln;
write('Enter MM DD YY '); readln( month, day, year);
if day<>0 then begin
JNUM  :=  Jul( month, day, year);
writeln('The Julian # of ',month,'/',day,'/',year,
' is ', JNUM:10:0);
JtoD( JNUM, month, day, year);
Writeln('The date corresponding to ', JNUM:10:0, ' is ',
month,'/',day,'/',year);
end;
end;
writeln('That''s all folks.....');
end.

(* end of file JULIAN.PAS *)
                                         ```