Change the records with abap in internal table

Hi experts,

In an internal table, i have some data. I want to modify all the records contained in the fieldC to a fixed value 'XXXX'

I tought about this treatment:

LOOP AT itab INTO str.     str2t2 = str.     str2-fieldC = 'XXXXX'.     APPEND str2 TO  itab.     CLEAR str2.   ENDLOOP.

It's working fine now, but i am afraid about performance in the future. What are you advices?

Any better way to perform it?

Thanks.

Amine