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I
80
Here is what this program will print:
The backspace codes in line 20 move the print head a total of
three spaces to the left so that the first part of line 30 will over-
print the word “NOT”. The delete codes in line 50 “erase” the
three letters in the word “NOT” so that it doesn’t even print.
In lrne 80, CHR$(24) deletes the words in line 70. The
semicolon at the end of line 70 prevents a line feed from causing
that line to print before the printer receives the CHR$(24) code.
The text in line 90 prints as it normally would because it is after
CHR$(24).
■ Printing zeroes
There are two types of zeroes. There is the one we use every
day – O– and this is what your printer will print as its default.
The other type is used almost exclusively in computers and
engineering. It is called the “slash zero” and is written like this
– 0. The line through the number prevents you from
misreading it as the letter “O”. Before high-quality printers
were available, this was a good idea but there is no special need
for it today (although you may want to use the slash zero for a
special effect).
■ Immediate-print
This printer can print at the quick rate of 120 characters per
second. But it will also print more slowly at the speed of your
typing. In the immediate-printmode, the print head prints one
character at a time, as you send it. The printer also moves the
paper up so that you can see the current line and then down to
continue printing.
You can turn the immediate-print mode on with (ESC) “i” 1.
Before looking at it, let’s review the normal operation of the
print buffer. Enter this program.