Now let's insert the missing HOW. You'll read: Now position the cursor over the A in ARE by pressing several times. Interesting? Think of the applications. If you want to repeat a com- plex statement several tines in the same program ... or if you want to change just a part of a statement on one line and enter that amended statement on another line. Exercise 8 - Using the reverse field Every key on the keyboard, with the exception of a few which we shall note, prints almost exactly what you see onto the screen. We say "almost" because the screen displays characters in white then to get past the READY in the display. Type LIST. You on a black background. There is a key which, when pressed.
causes all subsequent characters to be displayed in reverse field - black on white - on that line. With editing that easy you need have no fear of making typing errors. Agreed? Let's try another interesting screen edit. First, type NEW to clear out the old program. Enter: Type A B C A B C and you'll see: 1 0 P R I N T "ANYTHING" Your PET displays 128 unique symbols which, with the addition of reverse field, really adds up to a total of 256 different characters that can be displayed. (This time we won't type LIST each time we make a correction.) Press and so that you position the cursor over 1 Reverse field remains in effect until a) you type RETURN or b) in line # 10.
you Press 2 then press until it reaches the A in ANYTHING" Now type EVERYTHING" and press As an example, type: Now press together so that you position the cursor over the 2 in line #20. Press 3 then over to the E in EVERYTHING and type NOTHING". Press SPACE three times. ( Because EVERYTHING is three letters longer than NOTHING.) Press Now type LIST and press 14 1 5