Hi Sanjana,
Have the field of work area of your final internal table with type as String and it works perfectly fine.
Previous comments have already given this,
still -
Working code
TYPES : BEGIN OF ty_char,
record TYPE string,
END OF ty_char.
DATA : ls_char TYPE ty_char,
lt_char TYPE STANDARD TABLE OF ty_char.
do 256 times.
concatenate 'A' 'A' 'A' 'A' ls_char-record into ls_char-record.
enddo.
append ls_char to lt_char.
-> LT_CHAR will have 1024 characters.
BR.