[KRIK]

Ладно, вообщем кому интересно - протестите плиз, вроде работает как надо.

uses
  SysUtils;

var
  i,j,k,max,buf:integer;
  file1:file of integer;
  v,t_var:integer;
begin
  Assignfile(file1,'res.dat');
  rewrite(file1);
  RANDOMIZE;
  for i:=0 to 5 do begin
    buf:=random(50)+1;
    write(file1,buf);
    writeln(inttostr(buf));
  end;
  closefile(file1);



  reset(file1);
  i:=0;
  //while not eof(file1) do begin
  For k:=0 to 5 do begin
    seek(file1,i);
    read(file1,max);
    t_var:=i;

    for j:=i to 5 do begin
        seek(file1,j);
        read(file1,v);    ///
        if max<v then begin
          max:=v;
          t_var:=j;
        end;
    end;

  seek(file1,i);
  read(file1,buf);
  seek(file1,i);
  write(file1,max);
  seek(file1,t_var);
  write(file1,buf);

  inc(i);
  end;
  closefile(file1);

  reset(file1);
  writeln('');
  for i:=0 to 5 do begin
    read(file1,buf);
    writeln(buf);
  end;
  closefile(file1);

  readln;
end.