TUTORIAL 1 -StringCompression
• Advanced BASiC programming
• tutorial. By Martin Johansson
• April 2001
• smoother_1982@hotmail.com
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For you non C++ programmer, /!=/ means not equal. [2nd] [Math] 2
/->/ is the store botton.


• Following algorithm can help you saving space in your games.
By using it you avoiding unnessesary memory. Example: you have created
a game which contains 10 levels in it. You thought you were smart
when you stored the levels in a matrix by using this method:

:If L=1:then
:[[1,1,1,1][1,0,0,1][1,1,1,1]]->[A]:End
(this makes a square)

	( [[1,1,1,1]
	   [1,0,0,1]
	   [1,1,1,1]] )


If you instead creat a string and enter all your numbers after each
other like this:

:"111110011111"->Str1

now have you saved alots of bytes. But good brings always bad, because now
you have to have a decompression algorithm that uncompress the string to 
your
matrix, I have come up with a litle one like this:

(remember the string?: "111110011111"->Str1)

PROGRAM:STR2MTRX
:3->R:4/->/C			// R=ROW, C=COLUMN
:{R,C}/->/dim([A])
:1->F
:For(A,1,length(Str1))
:exp(sub(Str1,A,1))/->/[A]((fPart(A/4)/!=/0)+ipart(A/4),F)
:F(F<4)+(F<4)+(F=4)/->/F
:End

Now have the program decompressed the string into the matrix. After your 
done with
the matrix just typ: Delvar [A], then its deleted.
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If you download my game, DStar v1.1 SE, then you can see that I have used 
this code
for making small levels. But its just a introducing thing, your not actually 
saving
space in that game because it just using one matrix, [A].


/Martin Johansson