DATA: BEGIN OF line,
col1 TYPE i VALUE '11',
col2 TYPE i VALUE '22',
col3 TYPE i VALUE '33',
END OF line.
DATA comp(5) TYPE c VALUE 'COL3'.
FIELD-SYMBOLS: <f1> TYPE ANY, <f2> TYPE ANY, <f3> TYPE ANY.
ASSIGN line TO <f1>.
ASSIGN comp TO <f2>.
DO 3 TIMES.
ASSIGN COMPONENT sy-index OF STRUCTURE <f1> TO <f3>.
WRITE <f3>.
ENDDO.
ASSIGN COMPONENT <f2> OF STRUCTURE <f1> TO <f3>.
WRITE / <f3>.