Atari 400 User Manual

108 User's Handbook to the Atari 400/ 800 Computers
EXAMPLE
10 DIM A$(10)
20 READ A$
30 PRINT A$
40 DATA I N DEPENDENCE DAY
RUN
INDEPENDEN
The preceding example shows that the st ring variable A$ is
dimensioned to 10 characters at line 10. However , during the
program , A$ is assigned a 16 character string with the READ
statement at
line 20. Since room for only 10 characters was set
aside in
memory , only the first 10 characters of the DATA item
are assigned to A$. The PRINT statement in line 30 displays the
contents of A$. It can be seen from the output that A$ only has 10
characters.
The
DIM statement must be executed before an INPUTor READ
occurs.
If the DIM statement of the previous example was
deleted , the following m essage would occur .
ERROR-9 AT
LINE 20
If a variable is dimensioned twice in the same program (without
CLR), ERROR-9 occurs.
The
maximum size of st ring variables depends on the amount of
available memory at the time of the DIM statement.
Dimensioning numeric variables determines the number of
elements that the variable can contain, not the length. A
subscript
is the numb er that follows a variable name (in
parentheses) and indicat
es which element of that variable is
considered. The following exa mple shows how to assign 4 values
to a subscripted variable.

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)