Atari 400 User Manual

Advanced Atari BASIC 77
the following program , a substring is used to change X$ from
"JOHN JOH NSON" to "JOHN J ACKSON".
100 DIM X$(15)
200 X$ = "JOHN JOHNSON"
300 X$(6,1 2) = "JACKSON"
400 PRINT X$
500 END
RUN
JOHN JACK SO N
If an e rror occurs with a s ub st ring specificat ion , error number 5
will be di sp layed.
String Concatenation
The process of joinin g together one or more strings is known as
co ncate nation . Th e LEN function is used in co njun ct ion with
substrings in concatenation. Th e LEN function is us ed to return
the l engt h of its string arg um en t. L EN u ses the following
config ur ation.
LE N (string)
The following program illu strates st ring con ca tenation in Atari
BASIC.
100
DIM X$(15), Y$ (15)
150 X$ = '''':Y$ = ""
200 X$ = "J OHN"
300 Y$ = "JOHNSON"
400 X$( LEN (X$) + 1) = Y$
500 PRINT X$
600 END
RUN
JOHNJOHN SON
The actual concatenati on takes place in lin e 400. Here, Y$ is
added
onto the end of X$ to form a new X$. Notice that 1 was
added to the result of LEN(X$) . This ca u ses Y$ to be added
beginning at the first blank space following the end of the
original X$.

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)