Apple IIe - Manual (Page 30)

Page 30 of 74 IIe
Printed: Tuesday, March 4, 2003 10:40:15 AM
Pressing Return lets the computer know when you've completed a line or instruction. Since you
have to do it after every line in a BASIC program, you won't be reminded each time. From now
on, just remember: when you've finished typing a line or an instruction, be sure to press
Return.
Fixing Mistakes:
If you make a mistake while you're programming in Applesoft BASIC, use LEFT-ARROW to back up to
the scene of your error, then type over it, and use RIGHT-ARROW to get back to the end of the
line.
(DELETE won't work while you're in the BASIC programming environment.)
If you discover a typing mistake after pressing Return, just retype the line.
SYNTAX ERROR:
If you hear a beep and get the message SYNTAX ERROR, it means that you misspelled a BASIC
command or statement, like PRINT, and the program doesn't know what you're talking about, or
else it means you left out a quotation mark. If you get such a message, don't panic, just
retype the line.
DOS 3.3 Requires Uppercase:
DOS 3.3, another Applesoft BASIC operating system, accepts only uppercase statements and
commands.
ProDOS accepts instructions in either uppercase or lowercase.
Combining Statements to Create a Program
Now that you know how to fix mistakes, type HOME to clear the screen, type NEW to clear your
one-line program from memory, then try typing this slightly longer program.
Don't forget to
press Return after every line.
1 PRINT ROSES ARE RED 2 PRINT VIOLETS ARE BLUE 3 PRINT THIS IS AS EASY 4 PRINT AS TYING
YOUR SHOE 5 END
(The END statement lets the computer know that the program is finished.)
When you finish typing your program, try it out by typing RUN. The result should look like
this:
ROSES ARE RED VIOLETS ARE BLUE THIS IS AS EASY AS TYING YOUR SHOE
Notice that line 1 was executed first, then line 2, then line 3, and so on. It doesn't matter
in which order you type the lines; the computer will carry them out from lowest to highest line
number.
If you don't believe it, type NEW (to clear the computer's memory), then retype the program in
a different sequence, like this:
NEW 3 PRINT THIS IS AS EASY 1 PRINT ROSES ARE RED 5 END 4 PRINT AS TYING YOUR SHOE 2 PRINT
VIOLETS ARE BLUE
Type RUN and see what happens.
Replacing Statements
If you decide you want to replace one of the statements in your program with another, all you
have to do is type the number of the line you want to replace and the new statement.
You don't
need to retype the whole program. Try typing this: