Atari 400 User Manual

50 User's Handbook to the Atari 400 /8 00 Computers
An array can also consist of two dimensions . Such an array is
known as a two-dimensional array (or table). An example of an
array
of 4 rows and 3 columns is shown in Illustration 3-2.
A
two-dimensional array contains two subscripts. The first
subscript
contains the row location , while the second subscript
contains
the column location . The subscripted variable A(l , O)
identifies the darkened area in the array shown in Illustration 3-
2.
Illustration 3-2. Two-Dimensional Array
Columns
°
1
2
°
1
Rows
2
3
I n the Atari BASIC, arrays can be used to represent numeric data.
String arrays
cannot be used in Atari BASIC.
Before any array variable can be us ed in a program , the size of
that array must have been defined so that BASIC can reserve a
memory area for it. This is also accomplished with the DIM
statement. A single dimension num eric array with 11 variables
could be defined with the following DIM statement:
DIM A(10)
Remember that array subscripts begin with 0. The refore , the
numeric array A which was dimensioned in the preceding
statement, would have space reserved for the 11 array elements,
not 10 .

Atari 400 Specifications

General

Manufacturer	Atari
Model	400
Type	Home Computer
Release Year	1979
CPU	MOS Technology 6502
CPU Speed	1.79 MHz
ROM	10 KB
Operating System	Atari OS
Keyboard	Membrane keyboard
RAM	8 KB (expandable to 48 KB)
Graphics	ANTIC and GTIA chips
Sound	4 channels
Display	RF output for connection to TV
Storage	Optional cassette tape drive or floppy disk drive
Ports	Cartridge
Display Resolution	320x192 (16 colors)