unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
  ComCtrls;

type
  Tperson = class;
  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Edit4: TEdit;
    Edit5: TEdit;
    GroupBox1: TGroupBox;
    GroupBox2: TGroupBox;
    Label1: TLabel;
    Label2: TLabel;
    ListView1: TListView;
    OpenDialog1: TOpenDialog;
    PageControl1: TPageControl;
    SaveDialog1: TSaveDialog;
    TabSheet1: TTabSheet;
    TabSheet2: TTabSheet;
    TabSheet3: TTabSheet;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Edit1Change(Sender: TObject);
    procedure Edit3Change(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure PageControl1Change(Sender: TObject);
  private
    { private declarations }
    procedure  addtoview(Person:Tperson);
  public
    { public declarations }
  end;

 type
  TStoredData = record
    A: Integer;
    B: Extended;
    C: array[0..25] of Char;
  end;

  TStoredObject = class
  private
    FA: Integer;
    FB: Extended;
    FC: array[0..25] of Char;
  public
    procedure LoadFromFile(AFile: THandle); virtual;
    procedure SaveToFile(AFile: THandle); virtual;
  end;
  Tperson = class
   FIO: string;
   number: integer;
    procedure LoadFromFile(AFile: THandle); virtual;
    procedure SaveToFile(AFile: THandle); virtual;
  end;

  Master = class(Tperson)
  f1: single;
  procedure LoadFromFile(AFile: THandle); override;
    procedure SaveToFile(AFile: THandle); override;
  end;
  Buhg = class(Tperson)
  f2: integer;
  procedure LoadFromFile(AFile: THandle); override;
    procedure SaveToFile(AFile: THandle); override;
  end;
  Manager = class(Tperson)
  f3: array[0..15] of char;
  procedure LoadFromFile(AFile: THandle); override;
    procedure SaveToFile(AFile: THandle); override;
  end;
  TPersonCollection = class
  private
    FPersons: array of TPerson;
    function GetPerson(Index: Integer): TPerson;
    function GetCount: Integer;
  public
    procedure Add(Person: TPerson);
    procedure Delete(Index: Integer);
    procedure clear;
    procedure LoadFromFile(const filename: string);
    procedure SaveToFile(const filename: string);
    property Count: Integer read GetCount;
    property Persons[Index: Integer]: TPerson read GetPerson; default;
  end;


var
  Form1: TForm1;
  Count: integer =-1;
  Persons: TPersonCollection;

implementation

{$R *.lfm}

{ TForm1 }

procedure WriteString(AFile:THandle; const s:string);
var
  Len:Integer;
  i: integer;
begin
Len:= Length(S);
FileWrite(AFile, Len, sizeof(Len));
FileWrite(AFile, PByte(S)^, sizeof(S[i])*Len);
end;
function ReadString(AFile:THandle):string;
var
  Len:Integer;
  i: integer;
  begin
  FileRead(AFile, Len, sizeof(Len));
  SetLength(Result, Len);
  FileRead(AFile, PByte(Result)^, sizeof(Result[i])*Len);
  end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  persons:= tpersoncollection.create;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  i: integer;
begin
  If OpenDialog1.Execute then
  begin
    persons.LoadFromFile(opendialog1.FileName);
    Listview1.items.beginupdate;
    listview1.items.clear;
    for i:=0 to persons.count-1 do
    addtoview(persons[i]);
    listview1.items.EndUpdate;
  end;

end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  ListView1.clear;
  Persons.clear;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  If SaveDialog1.Execute then
  begin
    persons.savetofile(savedialog1.filename);
  end;

end;

procedure TForm1.Button4Click(Sender: TObject);
  var
  SamplePerson: TPerson;
begin
  case pagecontrol1.TabIndex of
  0: SamplePerson := Master.Create;
  1: SamplePerson := Buhg.Create;
  2: SamplePerson := Manager.Create;
  end;
  sampleperson.fio:= edit1.text;
  sampleperson.number:= strtoint(edit2.text);
  if sampleperson is master then
  master(sampleperson).f1:= strtofloat(edit3.text);
   if sampleperson is Buhg then
  buhg(sampleperson).f2:= strtoint(edit4.text);
   if sampleperson is Manager then
  manager(sampleperson).f3:= edit5.text;
  Persons.Add(SamplePerson);
  addtoview(sampleperson);
end;

procedure TForm1.Edit1Change(Sender: TObject);
begin

end;

procedure TForm1.Edit3Change(Sender: TObject);
begin

end;

procedure TForm1.PageControl1Change(Sender: TObject);
begin

end;

procedure TStoredObject.LoadFromFile(AFile: THandle);
var
  IntData: TStoredData;
begin
  FileRead(AFile, IntData, sizeof(IntData));
  FA := IntData.A;
  FB := IntData.B;
  FC := IntData.C;
end;
procedure TStoredObject.SaveToFile(AFile: THandle);
var
  IntData: TStoredData;
begin
  IntData.A := FA;
  IntData.B := FB;
  IntData.C := FC;
  FileWrite(AFile, IntData, sizeof(IntData));
end;
procedure TPerson.LoadFromFile(AFile: THandle);
  begin
    FIO:= ReadString(AFile);
    FileRead(AFile, number, sizeof(number));

  end;

  procedure TPerson.SaveToFile(AFile: THandle);
   begin
    WriteString(AFile, FIO);
    FileWrite(AFile, number, sizeof(number));
   end;
procedure TPersonCollection.Add(Person: TPerson);
var
Len: Integer;
begin
  Len := Length(FPersons);
  SetLength(FPersons, Len+1);
  FPersons[Len] := Person;
end;
procedure TPersonCollection.Delete(Index: Integer);
var
i: integer;
begin
 for i:= Index+1 to Length(FPersons)-1 do
 FPersons[i-1]:= FPersons[i];
 SetLength(FPersons, Length(FPersons)-1);
end;
function TPersonCollection.GetPerson(Index: Integer): TPerson;
begin
 Result:=FPersons[Index];
end;
 function TPersonCollection.GetCount: Integer;
 begin
 Result:= Length(FPersons);
 end;
 procedure TPersonCollection.clear;
 var
 i:integer;
 begin
 for i:=0 to Length(Fpersons)-1 do
 Fpersons[i].free;
 setlength(Fpersons, 0);
 end;

 procedure  Tform1.addtoview(Person:Tperson);
 var
 newitem: Tlistitem;
 begin
   newitem:= listview1.Items.add;
   newitem.caption:= person.fio;
   newitem.subitems.add(inttostr(person.number));
   if person is master then
     newitem.subitems.add(floattostr(master(person).f1));
   if person is buhg then
     newitem.subitems.add(inttostr(buhg(person).f2));
   if person is manager then
     newitem.subitems.add(manager(person).f3);
 end;

 procedure TPersonCollection.LoadFromFile(const filename: string);
 var
 AFile: Thandle;
 sig: integer;
 newperson: TPerson;
 begin
   clear;
   AFile:= FileOpen(filename, fmopenread);
   while FileRead(AFile, sig, sizeof(sig)) >0
   do
   begin
   case sig of
     101: Newperson:= Master.Create;
     102:  Newperson:= Buhg.Create;
     103:  Newperson:= Manager.Create;
   end;
   Newperson.LoadFromFile(AFile);
   Add(NewPerson);
   end;
   fileclose(AFile);
 end;

 procedure TPersonCollection.SaveToFile(const filename: string);
 var
 AFile: Thandle;
 sig: integer;
 i: integer;
 begin
 AFile:= FileCreate(filename);
 for i:=0 to Length(Fpersons)-1 do
 begin
   if FPersons[i] is Master then
   sig:=101 else
     if Fpersons[i] is Buhg then
     sig:=102 else
       if FPersons[i] is Manager then
       sig:=103;
   filewrite(AFile, sig, sizeof(sig));
   FPersons[i].SaveToFile(AFile);
 end;
 fileclose(AFile);
 end;
 procedure Master.LoadFromFile(AFile: THandle);
 begin
 inherited;
 fileread(AFile, f1, sizeof(f1));
 end;

 procedure Master.SaveToFile(AFile: THandle);
 begin
 inherited;
 filewrite(AFile, f1, sizeof(f1));
 end;
 procedure Buhg.LoadFromFile(AFile: THandle);
 begin
 inherited;
 fileread(AFile, f2, sizeof(f2));
 end;

 procedure buhg.SaveToFile(AFile: THandle);
 begin
 inherited;
 filewrite(AFile, f2, sizeof(f2));
 end;
 procedure Manager.LoadFromFile(AFile: THandle);
 begin
 inherited;
 fileread(AFile, f3, sizeof(f3));
 end;

 procedure Manager.SaveToFile(AFile: THandle);
 begin
 inherited;
 filewrite(AFile, f3, sizeof(f3));
 end;

end.