I
84
The following program shows how these codes work.
10 LPRINT "BACKSPACE DOES NOT";
20 LPRINT CHR$(8);CHR$(8);CHR$(8);
30 LPRINT 'I=== WORK"
40 LPRINT "DELETE DOES NOT";
50 LPRINT CHR$(127);CHR$(127);CHR$(127);
60 LPRINT “WORK”
70 LPRINT "CANCEL LINE";
80 LPRINT CHRs(24);
90 LPRINT "DOES NOT WORK"
Here is what this program will print:
The backspace codes in line 20 move the printhead a total
of three spaces to the left so that the first part of line 30 will
overprint 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 line 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).
n Printing zeroes
There are two types of zeroes. There is the one we use every
day - 0 - 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 “0”. 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).