HIDE Command in ABAP

Question

What is the exact purpose of using a HIDE statement while making an interactive report? I know it is needed , but what purpose it exactly solves.

Answer 1

F1 help.....
HIDE
Basic form
HIDE f.
In an ABAP Objects context, a more severe syntax check is performed that in other ABAP areas. See Constants not allowed in HIDE area.
Effect
Retains the contents of f related to the current output line. When the user selects the line from the list f is automatically filled with the retained value.
The selection can occur in:
AT LINE-SELECTION
AT PFx
AT USER-COMMAND
READ LINE
The contents of the field do not have to have been displayed using WRITE in order for you to retain them.
The HIDE statement does not support deep structures (structures that contain internal tables).
Useful system fields for interactive reporting are listed in the System Fields for Lists documentation.
Note
Lines or components of lines of an internal table that you address using a field symbol (see ASSIGNING addition to the READ and LOOP statements), cannot be retained using HIDE. You can store them using a global variable instead.
Note
Runtime errors:
HIDE_FIELD_TOO_LARGE: The field is too long for HIDE.
HIDE_ON_EMPTY_PAGE: HIDE not possible on an empty page.
HIDE_NO_LOCAL: HIDE not possible for a local field.
HIDE_ILLEGAL_ITAB_SYMBOL: HIDE not possible for a table line or component of a table line.
and also a sample program.
data: begin of itab occurs 0,
      field type c,
      end of itab.
itab-field = 'A'.  append itab.
itab-field = 'B'.  append itab.
itab-field = 'C'.  append itab.
itab-field = 'D'.  append itab.
itab-field = 'E'.  append itab.
loop at itab.
  format hotspot on.
  write:/ itab-field.
  hide itab-field.
  format hotspot off.
endloop.
at line-selection.
  write:/ 'You clicked', itab-field.
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