Contents of the README.TXT file
V_ARRAY.ZIP Contains the following files:
VIR.H 2351 -Header file for virtual array functions
VIR.OBJ 4911 -Object file containing virtual array functions
PRIMES.C 2325 -Prime number generator source code
PRIMES.EXE65392 -Prime number generator program
README.TXT 4079 -This text file
The program PRIMES is a demonstration using a virtual array. To run
the program, simply type PRIMES at the DOS prompt. You will find that the prime
number generator quickly generates a large volume of primes. To stop the pro-
gram, simply press a key (I suggest ). Whatever key you hit will be
passed on as if it was typed at the DOS prompt.
PRIMES produces a file containing each prime number it generates. The
prime numbers are stored as an array of long integers. PRIMES is capable of
producing a list of all prime numbers less than 2,000,000,000 if you have the
file space for it. Since such a large volume of prime numbers would take some
time to compile, PRIMES has been designed to pick up where it left off when it
is restarted. The file containing the prime numbers is named PRIMES.DAT.
The virtual array functions in VIR.* are designed to allow access to
an arbitrarily large array. Any type of data or structure can be accessed with
these functions. Array access is straight forward, allowing your code to be
simple and uncluttered. All disk caching / swapping is done automatically by
VIR doubles as a buffered file access method. Since the arrays that
VIR produces become disk files, any disk file can be accessed as an array of
elements. (For instance, characters, data records,..) VIR has provisions for
file sharing such as locking and unlocking groups of elements or denying access
to files. In fact, VIR was developed as the primary file access method for a
multi-user relational data base.
When initializing a virtual array, you are required to specify the
buffering characteristics. By altering these, you can achieve significant
improvements in overall program performance as well as insuring automatic
transaction reversal (Requires TTS) in the event of a program crash.
Since VIR takes care of all these nasty details, your application can
get on with nifty algorythms such as shown in this demo. In fact, with an extra
macro or two, you can access a virtual array almost the same as if it were a
BUT ENOUGH EXPLAINING....
The purpose of this demo is to bring in a couple dollars and give out a
nifty little bit of code. Feel free to use these functions in any of your pro-
grams. (if you can figure it all out.) It was compiled using the SMALL memory
model under TURBO C V2.0. I wish to ecnourage you to evaluate them. GOOD LUCK!
If you come up with anything really nifty using this limited version,
it would be nice to see my name mentioned in your source credits. I would also
like to see a copy of the program and any comments you might have on how to
improve the functions.
Feel free also to pass this demo on to anyone you think might have a
use for it.... especially other BBS's! However, all of these files must remain
intact and complete!
If you really want to be able to use these functions, simply send $10.00 to me:
Peter G. McNeil
c/o Persnickety Inc.
22446 Davis Drive #187
Sterling, Va. 22170
DAY (703) 450-6727
EVE (301) 725-3239
FAX (703) 450-5574
FOR THIS YOU GET!!!
-Complete source code for the VIR fucntions.
-An explanation of each function and it's use.
-A discussion of the caching/swaping algorythm.
-A discussion of mult-user file access methods using VIR.
PLEASE SPECIFY 3.5" or 5.25" disk.
If you are a teacher and you want to use this in your class, I would be so
tickled that I would send it to you for free! Just send me a letter on official
letter head and it will be on it's way.
This code represents a lot of thought, develpment, testing, and
frustration. I hope it comes to some good use for you. It has proven very
useful to me. Thanks!!