Commodore Plus 4 - Keyboard colors

BASIC Version 3.5 Commands, Functions, and System Variables 41
A negative STEP value decreases the value of the counter variable each time
the loop is executed. (Remember that adding a negative value is like subtracting.)
3. The commands that are to be repeated during loop execution appear
between the FOR command and the NEXT command.
4. The NEXT command tells the computer to go back to the FOR command.
When the FOR command is reached again, the STEP value is added to the value
of the counter. When the counter passes the ending point, the loop terminates.
Never leave a FOR . . . NEXT loop with a GOTO. You can always leave when
NEXT is executed by setting the loop variable equal to its ending point.
Note: A FOR... NEXT loop is always executed once. The counter variable is
updated before leaving the loop.
The NEXT command can contain the FOR counter variable, but it is not
required. If you are nesting loops, use the counter variable in the NEXT com
mands to avoid errors. The NEXT command can also contain a number of
counter variables for nested loops. The variables must be listed starting with the
innermost loop variable and ending with the outermost loop variable, therefore,
nesting rules are followed.
Nesting Multiple FOR... NEXT Loops You can nest up to 10 FOR... NEXT
loops. Note the following when you nest loops:
• The inner loop becomes part of the outer loop.
• The inner loop must start and end between the beginning and ending of the
outer loop.
• The inner loop executes a full cycle from starting to ending points each time the
outer loop executes once.
Chapter 3 contains more information on using loops in BASIC programs.
Examples: 10 FOR X = 10 TO 50 STEP 15
SO PRINT "X ="; X
30 NEXT
40 PRINT "AT THE END OP THE LOOP, X =";X
RUN
X= 10
AT THE END OF THE LOOP, X = 55
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