Apple IIe - Page 102

102 Apple lie Users Handbook
The program lines following the FOR statement will be executed
until the NEXT statement is encountered. At this point , the
counter is incremented (assuming positive STEP value) by the
STEP value.
The value
for the counter is then compared with its final value b.
As long as the counter's value does not exceed the final value,
the program will branch back to the statement following the
FOR statement. This entire process will then be repeated.
When the counter 's value exceeds the specified final value (b),
the statement following the NEXT statement will be executed.
This will exit the FOR .. NEXT loop.
One FOR .. NEXT loop may be placed within another FOR .. NEXT
loop. This is known as nesting or nested loops. When FOR .. NEXT
loops are nested, each FOR .. NEXT loop must use a different
variable name for the counter. Also, the NEXT statement for the
inside loop must appear before the NEXT statement for the
outside loop. However, if both loops end at the same point, a
single NEXT
statement may be used to end these. Be certain that
the variable for the inside loop appears before the variable for
the outside loop. A NEXT statement such as the following :
NEXT J,I
would be interpreted as follows:
NEXT J
NEXT I
Example
10 FOR X = 1 TO -2 STEP -1
20 PRINT X
30 NEXT X
40 END
]RUN [Ret]
1
0
-1
-2
(