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"Hugo Palma" <hmpalma@mail.telepac.pt> wrote:

>I'm doing a project,but i'm just not able to save a variable of type LIST
>as shown below.
>I'm only able to save the first segment of the list,and none of the next.
>Can anyone please help me.
>Thanks.
>
>type
>   list=^no;
>   no=record
>      v:integer;
>      seg:list;
>      end;
>
>var
>   p:list;
>

Mmmmm, you stopped short of including the code that you have that succeeds in
writing the first entry.  A small example would have been nice.

Have your procedure that writes the list implement a while loop, stopping when
the list pointer becomes nil.  After writing the current list entry it would
advance the pointer to the "next" seg.  This assumes that the last entry in the
list is identified by a nil seg field.  Also be certain that the pointer you use
to "walk" the list is a local variable or a parameter by value.  You wouldn't
want to loose the list by changing the actual list pointer.

    ...red
cc

Hello.

Hugo Palma <hmpalma@mail.telepac.pt> wrote in article <01bc2d75$4541e060$LocalHost@host.telepac.pt>...
> I'm doing a project,but i'm just not able to save a variable of type LIST
> as shown below.
> I'm only able to save the first segment of the list,and none of the next.
> Can anyone please help me.
> Thanks.
> 
> type
>    list=^no;
>    no=record
>       v:integer;
>       seg:list;
>       end;
> 
> var
>    p:list;

Make a new record type to save and load the data:

    type
        no_for_save_and_load = record  { Define a record type which doesn't have }
            v: integer;                { the pointer field to next record.       }
        end;
    var
        f: file of no_for_save_and_load;
        data: no_for_save_and_load;

    begin
        assign(f, 'filename.dat'); { if Delphi, assignfile() }
        reset(f);
        while p^.seg <> nil do begin
            data.v := p^.v;   { substitute all fields to the record type data }
            writeln(f, data); { save }
            p := p^.seg;      { substitute next record }
        end;
        close(f); { if Delphi, closefile() }
    end;


-----------------------------------------------------------------------
Mail: shimaden@annie.co.jp   Home Page: http://www.annie.co.jp/~shimaden/
Hiroyuki Shimada
-----------------------------------------------------------------------

In article <01bc2d75$4541e060$LocalHost@host.telepac.pt>, 
"Hugo Palma" <hmpalma@mail.telepac.pt> wrote:

> I'm doing a project,but i'm just not able to save a variable of type LIST
> as shown below.
> I'm only able to save the first segment of the list,and none of the next.
> Can anyone please help me.
> Thanks.
> 
> type
>    list=^no;
>    no=record
>       v:integer;
>       seg:list;
>       end;
> 
> var
>    p:list;
> 
> 
> 
> Please reply to :
> hmpalma@mail.telepac.pt

Hi, Hugo,

  Your code fragment is not enough.  The 'list' type is typical record for
'Linear List' items.  There are some way to build a linear list from this
type.  How do you build it?

  for very easy example, consider the following code;

Program SomeProgram;
type
  list = ^no
  no = record
    v : integer;
    seg : list
  end;
var
  root, p : list;
  f          : file of integer;
begin
(* building up a LIFO linear list *)
  root := nil;
  while {more data} do begin
     new(p);
     p^.v := {data};
     p^.seg := root;
     root := p
  end;
(* save it *)
  {set up f}
  p := root;
  while p<>nil do begin
     write(f, p^.v);
     p := p^.seg
  end;
  {close f}
...
end.

  It is important that saving pointer itself (i.e. saving p or p^.seg )
has no meaning and must be avoided.  Because pointer variables are
carrying addresses of contents and the addresses varies run-to-run
(under many modern OSs).

Haruo.

-- 
Haruo Toda, Niigata Univ.