Coding a loop
Use the PERFORM . . . TIMES
statement
to execute a procedure a specified number of times.
About this task
PERFORM 010-PROCESS-ONE-MONTH 12 TIMES
INSPECT . . .
In the example above, when control reaches the PERFORM
statement,
the code for the procedure 010-PROCESS-ONE-MONTH
is
executed 12 times before control is transferred to the INSPECT
statement.
Use the PERFORM
. . . UNTIL
statement to execute a procedure until a condition
you choose is satisfied. You can use either of the following forms:
PERFORM . . . WITH TEST AFTER . . . . UNTIL . . .
PERFORM . . . [WITH TEST BEFORE] . . . UNTIL . . .
Use
the PERFORM . . . WITH TEST AFTER . . . UNTIL
statement
if you want to execute the procedure at least once, and test before
any subsequent execution. This statement is equivalent to a do-until
structure:
In
the following example, the implicit WITH TEST BEFORE
phrase
provides a do-while structure:
PERFORM 010-PROCESS-ONE-MONTH
UNTIL MONTH GREATER THAN 12
INSPECT . . .
When control reaches the PERFORM
statement,
the condition MONTH GREATER THAN 12
is
tested. If the condition is satisfied, control is transferred to the INSPECT
statement.
If the condition is not satisfied, 010-PROCESS-ONE-MONTH
is
executed, and the condition is tested again. This cycle continues
until the condition tests as true. (To make your program easier to
read, you might want to code the WITH TEST BEFORE
clause.)