(49G) Friday 13th calculation

[Gerald H]

The programme returns the dates of Friday 13th for a valid year entry using dd.mmyyyy format.

The programme works for versions 1.19-6 & 2.10-8.

Eg For 1,953 the programme returns 13.021953, 13.031953 & 13.111953.

::
CK1&Dispatch
BINT1
::
% 1000000.
%/
%13
%+
BINT12
ZERO_DO
% .01
%+
DUP
% 13.063
DDAYS
%7
%MOD
%0=
IT
DUP
LOOP
DROP
;
;

Improvements welcome.