What is pack and upack doing in this code ?

Question

Hello ABAP Experts,
wha is the purpose of unpack in this code below. ?
LOOP AT datapak ASSIGNING <fs>.
    UNPACK <fs>-zcurr_type TO <fs>-zcurr_type.
    UNPACK <fs>-zp0_type   TO <fs>-zp0_type.
    UNPACK <fs>-zp1_type   TO <fs>-zp1_type.
    UNPACK <fs>-zp2_type   TO <fs>-zp2_type.
    UNPACK <fs>-zp3_type   TO <fs>-zp3_type.
    UNPACK <fs>-zp4_type   TO <fs>-zp4_type.
    UNPACK <fs>-zp5_type   TO <fs>-zp5_type.
    UNPACK <fs>-zp6_type   TO <fs>-zp6_type.
    UNPACK <fs>-zp7_type   TO <fs>-zp7_type.
    UNPACK <fs>-zp8_type   TO <fs>-zp8_type.
    UNPACK <fs>-zp9_type   TO <fs>-zp9_type.
    UNPACK <fs>-zp10_type   TO <fs>-zp10_type.
    UNPACK <fs>-zp11_type   TO <fs>-zp11_type.
    UNPACK <fs>-zp12_type   TO <fs>-zp12_type.
  ENDLOOP.
Thanks,
BWer

Answer 1

F1 help for UNPACK.
<i>
UNPACK
Basic form
UNPACK f TO g.
Effect
Unpacks the packed field f and places it in thefield g with leading zeros. If g is too short, it istruncated on the left.
Example
DATA: P_FIELD(2) TYPE P VALUE 103,
      C_FIELD(4) TYPE C.
UNPACK P_FIELD TO C_FIELD.
P_FIELD: P'103C' --> C_FIELD: C'0103'
Notes
If f is not type P, it is converted to typeP (see MOVE).
g should always be type C. Otherwise, unwanted sideeffects may occur.
The sign in the packed number is ignored.
The same runtime errors may occur as occur with thePACK statement.
</i>
Regards,
Rich Heilman