348 The VIC 20
User
Guide
GETiI!
The GET External statement (GET#) receives single characters as input
from
an
external storage device identified via a logical file number.
Format:
GET#lf,var
The G ET# statement can only be used in program mode. G ET# fetches
a single character from an external device and assigns this character to
variable var. The external device
is
identified by logical file number
if.
This
logical file must have been previously opened by an
OPEN
statement.
GET# and GET statements handle variables and
data
input identically.
For details see the GET statement description.
Example:
10
GETi4.CI:
IF
C.-""
GOTO
lEI
Get a keyboard character. Reexecute
if
no character
is
present
GOSUB
The GOSUB statement branches program execution to a specified line
and allows a return to the statement following GOSUB. The specified line
is
a subroutine entry point.
Format:
GOSUB
In
The GOSUB statement calls a subroutine. The subroutine's entry point
must occur on line
In. A subroutine's entry point
is
the beginning
of
the
subroutine in a programming sense;
that
is
to say it
is
the line containing the
statement (or statements) that are executed first. The entry point need not
necessarily be the subroutine line with the smallest line number.
Upon completing execution the subroutine branches back to the line
following the GOSUB statement. The subroutine uses a
RETURN
state-
ment in order to branch back in this fashion.
A GOSUB statement may occur anywhere in a program; in conse-
quence a subroutine may be called from anywhere in the program.
Example:
100
OOSUB
2000
110
A=Bllle
Branch to subroutine at line 2000
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