126
The VIC 20
User
Guide
Creating a
Formatted
Display
Keep in mind the maximum possible length
of
each entry; this
is
especially important when you consider the VIC 20's limited number of
columns.
For
instance, a name with a
job
title, such as
"MAJOR
SEIDELL-DIR.
STRATEGIC
OPERA
TIONS,"will wrap around to the
next display lines. Allow space for such entries when you format a display.
Centering prompts on the display
will
also make it appear more orderly.
Formatted displays should be used in programs that require a good
deal
of
data
entry. Three distinguishing features of proper data entry tech-
niques are a readable, uncluttered display, clear directions to the operator,
and the ability
of
the operator to correct mistakes.
Programming
Cursor
Movement
If
you encountered the VIC 20's quote mode while entering program
statements, you will already know how to program cursor movement.
If you edit a program statement containing a string constant, VIC
BASIC will interpret a control key as
an
actual character within the string
you are trying to edit.
For
example, when you press the
CRSR
UP/DOWN
key
between the quotes in a string, it will appear as
an
inverse-video Q on the
screen. Instead of moving the cursor up
or
down one line as you intended,
VIC BASIC inserted the
CRSR
UP/DOWN
key into the string.
If
you print the
string containing the cursor control character, the cursor will move down.
The statement
1010R$ ..
"~"
sets up a string of
22
CRSR
DOWN characters which, when printed by a
PRINT
statement, will move the cursor down
22
rows. Likewise, a string
containing
21
CRSR/RIGHT
characters will move the cursor to the right
21
spaces.
1020
Ct-"
•••••••••••••••••••••
,"
These strings containing the cursor control characters will allow you to
display a character anywhere on the display screen.
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