DO - ABAP Keyword Documentation

ABAP - Keyword Documentation → ABAP - Reference → Program Flow Logic → Control Structures → Loops →

Syntax

DO [n TIMES].
[statement_block]
ENDDO.

Addition:

Effect

Unconditional loop. The statements DO and ENDDO define a control structure, which can contain a closed statement block statement_block.

Without the addition n TIMES, the statement block is repeated until it is exited using one for the statements for leaving loops. In particular, the statement EXIT is ideal for exiting a loop completely. Within the statement block, the system field sy-index contains the number of previous loop passes, including the current pass. In nested loops, sy-index always refers to the current loop.

Notes

If the addition n TIMES is not specified, the loop has to be terminated by a statement; otherwise the loop is processed endlessly. The profile parameter rdisp/max_wprun_time limits the maximum execution time of an ABAP program. If this is exceeded, the program is ended by the runtime environment.
If DO loops are used to construct values or fill internal tables, they can probably be expressed more elegantly using conditional iterations with FOR in constructor expressions.
The obsolete addition varying can be used to process a sequence of data objects in the memory.

Addition

... n TIMES

The addition n TIMES limits the amount of loop passes in a DO loop. n is a numeric expression position of operand type i.

The number value of n when entering the loop determines the maximum amount of passes of the statement block. The control structure ignores changes to the value n within the loop. If n contains a value less than or equal to 0, the statement block is not executed.

Example

Calculates and displays the first ten square numbers in a DO loop.

DATA square TYPE i.

DO 10 TIMES.
square = ipow( base = sy-index exp = 2 ).
cl_demo_output=>write( |{ sy-index } { square }| ).
ENDDO.
cl_demo_output=>display( ).

Continue
ENDDO