Whats the difference between...

Can someone explain the difference between :

Dim MyArray() as byte

and

Dim MyArray() as String * 1

I need to write a long string to an array, and I was wondering which type of array would be more suitable for rapid calculations.

This will be part of an Encryption DLL so i'll need testers later on if anyone is interested.

thanks.

[RealisticGraphics]

When you say

Dim MyArray() as String * 1

any string you pass to your array will be cut off after the first character. Whereas, if you dim as byte you must pass a ascii number for the character between 0 and 255.

If you dim as string and then fix the width(as above) the string can be any length that you determine up to 64K(2^16 characters long). For example

dim mystring as string * 300

would return a fixed length string 300 characters long.

I think I didnt explain enough:

I want to have the long string spread over the entire array, IE. one character per element. I dont mind if i have to convert to numbers, just as long as its fast to run.

[Sam Finch]

DON'T USE THE SECOND ONE.

I would use an array of longs and do the strings 4 characters at a time.

use copymemory to put the string into an array, then we're not using vb strings anymore. (vb strings are fairly slow)
(if 4 doesn't divide the length of your strings, ie you have a 9 letter string then use 3 longs to store it, you'll be left with 3 null characters at the end of your string when you decrypt it)

it'll take roughly as long to handle the long integer as it does the byte, but with the long you're handling 4 characters at once so it's nearly 4 times as fast.(probably not 4 in practice)


the strings will take longer, a string is actually a long pointer to an array of integers, to do a calculation with a string you have to look at the long pointer then look up the integer in question, so that's about half the speed of the byte.

[Phobic]

Find out for yourself; test both and time how long it takes to complete a phrase.

[kedaman]

I would choose the byte array, it's faster as you use numeric calculations. Also I have a fast algoritm encryption sample and a key encryption on my homepage.

[LG]

What is a purpose of doing this?

LG,
I am creating an encryption algorithm and using an array is the fastest way to do it. Now I need to know what sort of array is manipulated fastest by the CPU.

Sam,
I cant use the CopyMemory method because I am using VB to create the DLL, not C++.

Anyone:
How do I convert 3 or 4 characters into one Long value?

[kedaman]

If you're reading or writing from a file you could probably use get and put with a long array. Also, i'm almost sure that integer is fastest, but byte allow me to encrypt strings directly with strconv convertion method

I'm giving up on this idea because I cant get the algorithm to decrypt properly.

[kedaman]

Paste your algoritm here or send it to me and i'll have a look at what's wrong

well it works fine when encrypting, its just decrypting that screws up. there is no reason for this that I can see because all you have to do is run the encrypted text through the DLL again and that should be it.