Introduction | Language Structure | IB Statements | File System | Comet 32 Runtime | Index |
Syntax: |
FOR control-variable = start-count TO stop-count [STEP increment] . . . NEXT control-variable |
Discussion: |
The FOR statement starts a repetitive series of program
statements (i.e., a loop). The statements following a FOR
statement up to the associated NEXT
statement form the loop.
The control-variable parameter is a previously-defined numeric variable with sufficient length and precision to store the values specified by the start-count, stop-count, and increment parameters. The start-count parameter is the initial value assigned to the control-variable. It may be a numeric constant or numeric variable. The stop-count parameter is the maximum value assigned to the control-variable. Stop-count may be a numeric constant or numeric variable. When the maximum value has been reached, the statements inside the loop will be executed for a final time and program flow will continue at the statement immediately following the NEXT statement. (The control-variable will retain the maximum value assigned.) During the looping process, the value of the control-variable is incremented according to the increment parameter. If not specified, the increment is 1. The increment may be a numeric constant or numeric variable. FOR/NEXT loops may be nested to any level. |
Example 1: |
FOR VALUE = 1 TO 250 ! Start loop from 1 to 250 SQUARE = VALUE * VALUE ! Compute square PRINT (0) VALUE;SQUARE ! Print value and square NEXT VALUE ! Continue loop |
Example 2: |
FOR LINE = 1 TO 60 ! Loop from 1 to 60 READ (1,DATA) EXCP=9999 ! Read the next data record PRINT (2,INFO) ! Print a line on the printer NEXT LINE ! Continue loop |
Example 3: |
FOR I = J TO K STEP M ! Loop using variable values PRINT (0) "Value is: ";I ! Print the value NEXT I ! Continue loop |
Example 4: |
FOR ROW = 1 TO 50 ! Start outer loop (count 1 to 50) FOR COLUMN = 1 TO 200 ! Start inner loop (count 1 to 200) SUM=SUM+DATA(COLUMN,ROW) ! Add up array elements NEXT COLUMN ! Continue inner loop NEXT ROW ! Continue outer loop |