I am new in ABAP and I have to modify these lines of code:

```
LOOP AT t_abc ASSIGNING <fs_abc> WHERE lgart = xyz.
  g_abc-lkj = g_abc-lkj + <fs_abc>-abc.
ENDLOOP.

```

A coworker told me that I have to use a structure and not a field symbol.

How will be the syntax and why to use a structure in this case?