Loops

DO – ENDDO – Unconditional Loop
DO can be used to execute a certain lines of codes specific number of times.

DO 5 TIMES.
  WRITE sy-index.  " SY-INDEX (system variable) - Current loop pass
ENDDO.

Output

WHILE ENDWHILE – Conditional Loop
WHILE can be used to execute a certain lines of codes as long as the condition is true.

WHILE sy-index < 3.
  WRITE sy-index.
ENDWHILE.

Output

CONTINUE – Terminate a loop pass unconditionally.
After continue the control directly goes to the end statement of the current loop pass ignoring the remaining statements in the current loop pass, starts the next loop pass.

DO 5 TIMES.
  IF sy-index = 2.
    CONTINUE.
  ENDIF.
  WRITE sy-index.
ENDDO.

Output

CHECK – Terminate a loop pass conditionally.
If the condition is false, the control directly goes to the end statement of the current loop pass ignoring the remaining statements in the current loop pass, starts the next loop pass.

DO 5 TIMES.
  CHECK sy-index < 3.
  WRITE sy-index.
ENDDO.

Output

EXIT – Terminate an entire loop pass unconditionally.
After EXIT statement the control goes to the next statement after the end of loop statement.

DO 10 TIMES.
  IF sy-index = 2.
    EXIT.
  ENDIF.
  WRITE sy-index.
ENDDO.

Output