UM0715

Basic command

Doc ID 15798 Rev 2

9/24

FOR

The FOR statement consists of three parts, the initial set-up value, a TO value, and an optional

STEP value.

10 DIM array(100)

20 FOR I = 1 TO 100

30 PRINT I

40 NEXT I

will print hundred values. The variable in the NEXT statement must be the same as that in the

matching FOR.

FOR loops may be nested to a maximum depth of 32.

10 DIM chess(8,8)

20 FOR I = 1 TO 8

30 FOR J = 1 TO 8

40 chess(j,i) = 1.0

50 NEXT J

60 NEXT I

The step value does not need to be 1, and may be negative. For instance:

10 FOR I = 1 TO 10 STEP 2

20 PRINT I

30 NEXT I

40 FOR I = 10 TO 1 STEP ?0.3

50 PRINT I

60 NEXT I

The initial, to, and step values are calculated once on entering the FOR loop, they are then

constant.

10 LET x = 10

20 FOR I = 1 TO x STEP x/5

30 PRINT I

35 REM Next line has no effect

40 LET x = x + 1

50 NEXT I

If the TO value is lower than the initial value (or higher if the STEP value is negative) then the

loop does not execute. Control passes to the first matching NEXT.

It is important not to jump out of FOR ... NEXT loops, or get the nesting order wrong, otherwise

control flow will become confused. To terminate a loop prematurely, set the counter to the TO

value, and jump to the matching NEXT.

Usage

FOR id = numeric TO numeric STEP numeric

...

NEXT id

Table 1.

Basic commands (continued)

Name

Remarks