Commodore VIC-20 User Manual page 270

256
The VIC 20 User Guide
N ow you can enter the data from the keyboard.
20
INPUT
At
If you were entering numeric data, you could use a numeric variable such
as
A.
At some point you will want to end the data entry. Let's say that if you
enter XXX the computer will branch out of the routine.
30 IF AI • "XXX" THEN 60
If the input was not XXX, you'll want to save it on tape
40 PRINTlU, A.
and go back for more input.
50
OOTO
20
If you are done entering data, close the file.
60 CLOSE
1
To run this program, you should first wind a fresh tape all the way
forward and rewind it again until you can see where the nonmagnetic leader
and the actual magnetic tape meet. Make sure that this is in the center ofthe
cassette opening (see Figure 8-1).
Here's the complete program.
10
OPEN
1,1,2, "DATA FILE"
20
INPUT Af
30 IF At
III
"XXX" THEN 60
40 PRINTlU, A.
50 OOTO
20
60
CL.OSE
1
Now close the lid and run the program. The program will pause (and
the cursor will disappear) for a few moments while the file is opened and the
name of the file is written onto the tape. The cursor will return and a
question mark will appear. Enter some characters and press
RETURN.
After entering a few items, enter XXX. The cursor should disappear
again; this time the file is being closed and the data and end-of-file marker
are being written onto the tape.