Data types incompatable

Question

Hi friends here iam giving simple coding.
In this i got alpha  and  it-f1 are type incompatable.
both are charecter data types .y iam getting this error.plz let me know the solution.
Thanks in advanve.
data: begin of it1 occurs 10,
             f1,
             end of it1,
         it2 like it1 occurs 10 with header line,
         alpha(10) value 'ABCDEFGHIJ'.
   do 10 times varying
   it1-f1 from alpha0 next alpha1.
       append it1.
     enddo.
append lines of it1 from 2 to 5 to it2.
loop at it2.
     write it2-f1.
     endloop.
insert lines of it1 from 8 into it2 index 2.
skip.
loop at it2.
     write it2-f1.
     endloop.
loop at it2.
     if it2-f1 >= 'E'.
         insert lines of it1 to 1 into it2.
         endif.
    endloop.
skip.
loop at it2.
     write it2-f1.
     endloop.
skip.
it2[] = it1[].
loop at it2.
     write it2-f1.
     endloop.

Answer 1

Hi Deva,
check below F1 help for Varying addition.
Addition 1
... VARYING f FROM f1 NEXT f2
Effect
This addition is useful if you have a series of fields
of the same type and the same distance from each other.
f is a variable which you define in a DATA statement. On each loop pass, f contains a new value. The field f1 after "FROM" specifies the first value of the variable f, while the field f2 after "NEXT" specifies the value to be assigned to the variable f in the second pass. For each subsequent pass, the variable f contains the next value in the sequence determined by the distance between the fields f1 and f2 in memory.
The fields f1 and f2 should be type-compatible and convertible
to f.
If the value of f changes during the loop pass, the new value is then placed in the appropriate field fn assigned to f (transfer type: pass by value and result). If the loop pass terminates because of a dialog message, the new value is not passed back if f changes.
The addition ... VARYING f FROM f1 NEXT f2 can be used several times in a DO statement.
DATA: BEGIN OF WORD,
        ONE   VALUE 'E',
        TWO   VALUE 'x',
        THREE VALUE 'a',
        FOUR  VALUE 'm',
        FIVE  VALUE 'p',
        SIX   VALUE 'l',
        SEVEN VALUE 'e',
        EIGHT VALUE '!',
      END   OF WORD,
      LETTER1, LETTER2.
DO VARYING LETTER1 FROM WORD-ONE NEXT WORD-THREE
   VARYING LETTER2 FROM WORD-TWO NEXT WORD-FOUR.
  WRITE: LETTER1, LETTER2.
  IF LETTER2 = '!'.
    EXIT.
  ENDIF.
ENDDO.
If u see above example LETTER1 and WORD-ONE are of same type and length.
Hope this is clear.
Thanks,
Vinod.