C-PS/8 FOCAL, 1971
 1.01 C     CALNDR FROM 	PROGRAMMING LANGUAGES	 COPYRIGHT 1970               
 1.02 C     BY DIGITAL EQUIPMENT CORPORATION                                        
 1.03 C     LAST CHANGE: 8/13/71                                                    
 1.04 
 1.05 C     GIVEN THE MONTH/DATE/YEAR, THE "PERPETUAL                                 
 1.06 C CALENDAR" WILL TYPE THE DAY OF THE WEEK.                                      
 1.07 
 1.30 A "WHAT IS THE DATE
  (MM/DD/YYYY) ",M,K,C,!
 1.32 I (M-13) 1.35;T "IN ORDER TO MAKE ROOM FOR THE MONTHS, THERE WERE NO DAYS!"!;G 1.3
 1.35 I (K-32) 1.4;T "MONTHS WITH",%3,K," DAYS DON	T EXIST IN",%4,C,"!"!;G 1.3
 1.40 S C=C/100;S D=FITR(.1+100*(C-FITR(C)));S C=FITR(C)
 1.50 S M=M-2;I (M) 5.4,5.4;G 5.5
 5.40 S M=M+12;S D=D-1;I (-D) 5.5,5.5;S D=99;S C=C-1
 5.50 S X=FITR<FITR[2.6*M-.2]+K+D+FITR[D/4]+FITR(C/4)-2*C>
 5.60 I (X-6) 5.7,5.7;S X=X-7;G 5.6
 5.70 T !"THE DAY IS ";D 6.1
 5.80 I (M*1E6+K*1E4+C-Q) 5.9,5.85,5.9
 5.85 T ", TODAY !"
 5.90 T !!;G 1.3
 6.10 I (X) 6.26,6.2;I (X-2) 6.21,6.22,6.15
 6.15 I (X-4) 6.23,6.24;I (X-6) 6.25,6.26
 6.20 T "SUNDAY
 6.21 T "MONDAY
 6.22 T "TUESDAY
 6.23 T "WEDNESDAY
 6.24 T "THURSDAY
 6.25 T "FRIDAY";I (FABS(K-13)),6.3;
 6.26 T "SATURDAY
 6.30 T " THE 13TH!!"