Specifications

BASIC Stamp II

Parallax, Inc. • BASIC Stamp Programming Manual 1.8 • Page 261

For...Next

FOR

variable = start to end {STEP stepVal} ... NEXT

Create a repeating loop that executes the program lines between For

and Next, incrementing or decrementing variable according to stepVal

until the value of the variable passes the end value.

•

Variable

is a bit, nib, byte or word variable used as a counter.

•

Start

is a variable or constant that specifies the initial value of the

variable.

•

End

is a variable or constant that specifies the end value of the

variable. When the value of the variable passes end, the For...Next

loop stops executing and the program goes on to the instruction

after Next.

•

StepVal

is an optional variable or constant by which the variable

increases or decreases with each trip through the For/Next loop.

If start is larger than end, PBASIC2 understands stepVal to be

negative, even though no minus sign is used.

Explanation

For...Next loops let your program execute a series of instructions for a

specified number of repetitions. In simplest form:

reps var nib ' Counter for the FOR/NEXT loop.

FOR reps = 1 to 3 ' Repeat with reps = 1, 2, 3.

debug "*" ' Each rep, put one * on the screen.

Each time the For...Next loop above executes, the value of reps is

updated. See for yourself:

reps var nib ' Counter for the FOR/NEXT loop.

FOR reps = 1 to 10 ' Repeat with reps = 1, 2... 10.

debug dec ? reps ' Each rep, show values of reps.

For...Next can also handle cases in which the start value is greater than

the end value. It makes the commonsense assumption that you want to

count down from start to end, like so:

reps var nib ' Counter for the FOR/NEXT loop.

FOR reps = 10 to 1 ' Repeat with reps = 10, 9...1.

debug dec ? reps ' Each rep, show values of reps.