Charles Stevenson wrote on May 14, 2005 8:24 AM: > Do you know why dimensioned arrays were first limited to > only 1 or 2 dimensions in Pick or Info-Basic?
I started my computing life with BASIC on a PDP-11/03 and FORTRAN on a CDC Cyber 173 system. I believe the dimension limit was there to avoid complicated memory addressing. Dimensioned arrays were stored in consecutive memory. DIM X(10,10) reserved 121 spaces (0-based indexing was the default). In order to access X(5,7), you would take the base address of X and add 7*11+5 to get the correct memory address. This naturally expands when you increase dimensions. For example, DIM Y(10,10,10) for item Y(3,5,4) would calculate (4*11+5)*11+3 as the offset. Extending this to more dimensions is left as an exercise for the reader :-> (I knew there was a reason they made us learn assembly language...) --Tom Pellitieri Century Equipment ------- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
