A New Counter

FOR...NEXT is a loop like DO...LOOP, but a FOR...NEXT loop has its own counter built in. Try this:

 CLS
 FOR I = 1 TO 10
 PRINT I
 NEXT I

Much better than our last counter. This one stops on its own after counting to 10.

A Color Chart

Here's a color chart program using a FOR...NEXT loop.

 CLS
 FOR I = 1 TO 15
 COLOR I, 0
 PRINT I; "*** COLOR ***"
 NEXT I

STEP

FOR...NEXT can also do "step counting". Try this:

 CLS
 FOR I = 2 TO 20 STEP 2
 PRINT I
 NEXT I

That will count by 2's from 2 to 20. STEP tells QBASIC what to count by. Try changing it to count by 10's from 10 to 100.

FOR...NEXT can also count backwards if you use a negative STEP value:

 CLS
 FOR I = 10 TO 1 STEP -1
 PRINT I
 SLEEP 1
 NEXT I
 PRINT "BLAST OFF!"

"SLEEP 1" tells QBASIC to wait for one second, then continue.