Atari 800 Basic Reference Manual

GOTO (G.)
To prevent accidental triggering of a subroutine (which normally follows the
main program), place an END statement preceding the subroutine. The follow-
ing program demonstrates the use of subroutines.
H3 PRH-H ")"
:::·r_-1 :;, .·.F~~-~. E',:-!,H·. ~. i,F'L .... t ' ~ .- . E ,-,r ~-,- .. -., 'P 'F.'ET'jr•L'
-'" - L!.:r - r ·.liJ.::~_ I u .·· •, : ! f':.ri
30 >=:=100
4~-:-1 co::;tJE: 1 oo~J
5[ 1 ::<=120
6~1 GOSUE: 1 0(1 ~ 3
70 >::=50
:::o Go::;ut: 1 a·.;:Jo
90 Et·~D
1 ~1(1~1 '/=3::;::::-::
101[1 ;:-:;: ;; ::+\'
(Clear screen)
Figure 4-3. GOSUB / RETURN Program Listing
In the above program, the subroutine, beginning at line 1000, is called three
times to compute and print out different values of X andY. Figure 4-4 illustrates
the results of executing this program.
400 301-J
480 360
200 15(1
Figure 4-4. GOSUB / RETURN Program Run
Format: {GO TO} ae xp
GOTO
Examples: 100 GOTO 50
500 GOTO
(X + Y)
The GOTO command is an unconditional branch statement just like the GOSUB
command. They both immediately transfer program control to a target lin e
number or arbitrary express ion . How ever, using anything other than a con-
stant will make renumb er ing the program difficult. If the target line number is
non-existent, an error results. Any GOTO statement that bran ches to a
preceding line may result in an "e ndless " loop . Statements following a GOTO
statement will not be executed. Not e that a conditional branching statement (see
IF / THEN)can be us ed to br ea k out of a GOTO loop . The foll ow ing program il-
lustr ates two uses of th e GOTO command.
Program Stat eme nts 17

Atari 800 Specifications

General

Brand	Atari
Model	800
Category	Desktop
Language	English