Atari 800 Basic Reference Manual

DIM (DI.)
8
ARRAYS AND
MATRICES
An array is a one-dimensional list of numb ers assigned to subscripted va riables ;
e.g., A(O), A(1), A(2). Subscripts range from 0 to the dimensioned value. Figure
8-1 illustrates a 7-element arra y.
A(O)
A(1)
A(2)
A(3)
A(4)
A(S)
A(6)
Figure 8-1. Example of an Array
A matrix, in this context, is a two-dimensional table co ntaining rows and col-
umns. Rows run horizontally and columns run v erticall y. Matrix elements are
stored by BASIC in row -m a jor order. This means that a ll the e lem ents of the
first row are stored first, followed by all the elements of the second row, etc .
Figure 8-2 illustrates a 7 x 4 matrix.
Columns
M(O,O) M(0,1) M(0,2)
M(0,3)
M(1,0)
M(1 ,1)
M(1,2)
M(1,3)
M(2,
0) M(2,1)
M(2,2)
M(2,3)
M(3,
0) M(3,1)
M(3,2)
M(3,3)
M(4,0) M(4,1) M(4,2) M(4,3)
M(5,
0) M(5,1) M(5,2) M(5,3)
M(6,0) M(6,1) M(6,2)
M(6,3)
Figure 8-2. Example of a Matrix
This section describes the two commands associated with arrays, matrices, and
strings, a nd how to load both arrays and matrices. The com~a nds in this se c-
tion are:
DIM
CLR
Format:
D M { svar(aexp) }
1
mvar(aexp[ ,aexp])
IJ{ ,svar(aexp) }tl
~ ,mvar(aexp[ ,aexp ... ] U
Examples: DIM A(100)
DIM M(6,3)
DIM B$(20)
used w ith STRINGS
An a ,v s and Matr·ices 41

Atari 800 Specifications

General

Processor	MOS Technology 6502
Processor Speed	1.79 MHz
ROM	10 KB
Graphics	ANTIC and GTIA chips
Release Year	1979
Display Resolution	up to 320 x 192
Colors	128 colors
Sound	4 channels
Storage	Cartridge, cassette, floppy disk
Ports	Cartridge, serial, monitor
Operating System	Atari OS