Commodore VIC-20 User Manual page 112

98
The VIC 20 User Guide
This statement branches in the same way as a GOTO, but GOSUB
remembers the line number to which it should return. This is illustrated in
the following section.
GOSUB STATEMENT
110 GOSUB 2000
110 \
I
I
Subroutine
)000
I
-start
I
I
2150 RETURN-end
\
\
\
\
\
\
\
\
"" ,
' ...
..................
;",'/
#'
\
I
I
,
I
I
/
/
The RETURN statement causes a branch back to the line number that
the GOSUB statement remembered. The three-statement loop that
initializes array A(I), if converted into a subroutine, would appear as
follows:
113 REM MAIN PROGRAM
20 REM ',.'OIJ eRN DIMENSION A SUBROIJTINE'S VARIABLE IN THE
MAP~
313 REM PROGRAM. IT IS A GOOD IDEA TO DIMEtJSIOtJ ALL '.lARrABLES
50
REM AT THE START OF THE
MAIN
PROGRRM.
613 DIM A(99)
713
OOSUB 2131313
813 REM DISPLAY SOMETHING TO PROVE THE
RETUR~1
OCCURRED
913
PRINT"RETURNED"
lee
OOTO
lee
2131313 REM SUBROUTINE
213113
FOR
1=13
TO
99
213213 A( 1)"1
213313 PRINT A(
l) ,;
213413 NEXT I
213513 RETURN