a brief history lesson from the stone age
In Ye Olden Days, we wrote code like this
READ(5, 501) IA, IB, IC
501 FORMAT (3I5)
IF (IA) 777, 777, 701
701 IF (IB) 777, 777, 702
702 IF (IC) 777, 777, 703
703 IF (IA+IB-IC) 777, 777, 704
704 IF (IA+IC-IB) 777, 777, 705
705 IF (IB+IC-IA) 777, 777, 799
777 STOP 1
799 S = FLOAT (IA + IB + IC) / 2.0
AREA = SQRT( S * (S - FLOAT(IA)) * (S - FLOAT(IB)) *
+ (S - FLOAT(IC)))
WRITE (6, 601) IA, IB, IC, AREA
601 FORMAT (4H A= ,I5,5H B= ,I5,5H C= ,I5,8H AREA= ,F10.2,
+ 13H SQUARE UNITS)
STOP
END
£10 for anyone who can explain how and why this works and how to use it right this minute