URGENT!!!!! Field Symbols.

Hi Experts ,

I have a structure say , gs_str having fields:

P, A01 ,B01 ,C01 ,A02, B02, C02, ..............A20, B20, C20.

Even I have an Internal table say , gt_data having fields P, A ,B , C.

Here is the Sample Code :

Loop at gt_data into gs_data.

-

Here i have to find which value of gs_str-Ann will have same value as gs_data-A.

if gs_data-A = gs_str-Ann.

-

then do the following arithmetic operation for corresponding gs_str-Bnn ,

gs_data-C = gs_str-Bnn + 10.

Modify gt_data with gs_data.

endif.

endloop.

I believe it can be done using field symbols.....Pls suggest some way or provide a code extract.

Thanks.