From QB64 Wiki
NEXT is used in a FOR counter loop to progress through the loop count.
- NEXT is required in a FOR loop or a "FOR without NEXT" error will occur.
- The FOR variable name is not required after NEXT.
- NEXT can be grouped with other NEXTs in nested FOR loops using colons like NEXT: NEXT
- NEXT can also end more than one nested FOR loop using comma separated variables like NEXT i, j
- NEXT increases the FOR loop count, so after the loop is over the counterVariable's value will be stopValue + 1 (or stopValue + increment).
- NEXT is also used with the RESUME statement.
Example: Finding the FOR variable value AFTER a simple counter loop to 10.
FOR i = 1 TO 10 PRINT i; NEXT i PRINT "AFTER the LOOP, NEXT makes the value of i ="; i
1 2 3 4 5 6 7 8 9 10 AFTER the LOOP, NEXT makes the value of i = 11
Result: The last value of i = 11 although FOR only looped 10 times. Only use the count values while inside of the loop or compensate for this behavior in your code.