Atari 400 Basic Reference Manual

IF/THEN
18 Program Statements
10 PRHH
20 F'~:ItH :PRINT "ONE
11
30 PR nn "n.~r
40 P~: HH "THPEP
50 PRI~H "FOUP"
6f1 P~:nn "FI'..JE
11
65 GOTO 101:1
70 PF.:ItH "$$$$$$$$$$$$$$$$$"
:::0 P F.~ I r-~T II~-~~-~;-~~-~~-~~-~~-~~-~~·~~-~~ - ~~ - ~~-~~-~~-~~-~~-~"
90 F•k: I t·iT
11
???'??????:?????'?'?? n
95 Et-iD
1 fij F'F.: H-iT !! ~=;I:=-:: II
11(1 FtR I t·iT II ::;El.)Et ·f'
E'0 F'F.:It·H aEIGHF
130 F,F.: I f·~T II t·i1 t · ~E H
14(1 F)~~ I ~-iT !I TEf·~ II
150 GOTO 70
Figure 4-5. GOTO Program Listing
Upon execution, the numbers in the above listing will be listed first followed by
the three rows of symbols. The symbols listed on lines 70, 80, and 90 are ignored
temporarily while the program executes the GOTO 100 command. It proceeds
with the printing of the numbers "SIX" through "TEN ", then executes these -
cond GOTO statement which transfers program control back to line 70 . (This is
just an example. This program could be rewritten so that no GOTO statements
were used.) The program, w hen executed, looks like the follow ing:
Ot ·£
HID
Tl-f.:EE
FOUF.:
FI!..JE
~:;£1.,.1£ t · ~
EIGHT
t·HNE
THl
$$$$$$$$$$$$$$$$$
'?'??????'?' '?' ?''?'?'?'?' ? ??
Format:
Examples:
Figure 4-6. GOTO Program Run
IF aexp THEN { lineno }
statement [ :statement ... ]
IF
X = 100 THEN 150
IF A$ = " AT ARI " THEN 200
IF AA = 145 and BB = 1 THEN PRINT AA, BB
IF X = 100 THEN X = 0

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)