Commodore VIC-20 - GET

Appendix G: BASIC Statements 34 7
The start, end, and increment values are read only once, on the first
execution of the FO R statement. You cannot change these values inside the
loop. You can change the value
of nvar within the loop. This may be used to
terminate a FOR-NEXT loop before the
end value is reached: Set nvar to
the
end value and on the next pass the loop will terminate itself. Do not jump
out
ofthe FOR-NEXT loop with a GOTO. Do not start the loop outside a
subroutine and terminate it inside the subroutine.
FOR-NEXT loops may be nested. Each nested loop must have a
different
nvar variable name. Each nested loop must be wholly contained
within the next outer loop;
at most, the loops can end at the same point.
GET
The GET statement receives single characters as input from the
keyboard.
Format:
GETvar
The GET statement can be executed in program mode only. When a
GET statement
is executed, var is assigned a 0 value if numeric, or a null
value if a string. Any previo'us value
ofthe variable is lost. Then GET fetches
the next character from the keyboard buffer and assigns it to
var. If the
keyboard buffer
is empty, var retains its 0 or null value.
GET
is used to handle one-character responses from the keyboard.
GET accepts the
RETURN key as input and passes the value (CHR$(13)) to
var.
If var is a numeric variable and no key has been pressed, 0 is returned.
However, a 0
is also returned when 0 is entered at the keyboard.
If var is a numeric variable and the character returned is not a digit
(0-9), a ?SYNT AX
ERROR message is generated and the program aborts.
The GET statement may have more than one variable in its parameter
list, but it
is hard to use if it has multiple parameters.
GET var, var, ... , var
Example:
10 GET C'
18 GET D
if) GET AlBIC