TestForm

unit TestUnit;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.Menus, Vcl.StdCtrls, Vcl.Grids;

type
  TTestForm = class(TForm)
    MainMenu: TMainMenu;
    About1: TMenuItem;
    Fi1: TMenuItem;
    Open1: TMenuItem;
    Save1: TMenuItem;
    EditOfFirstValue: TEdit;
    EditOfSecondValue: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    CalculateButton: TButton;
    Label3: TLabel;
    OpenDialog: TOpenDialog;
    SaveDialog: TSaveDialog;
    Button1: TButton;
    procedure CalculateButtonClick(Sender: TObject);
    procedure FindSum(A: Integer; B: Integer);
    procedure Open1Click(Sender: TObject);
    procedure Save1Click(Sender: TObject);
    procedure FirstEditChange(Sender: TObject);
    procedure SecondEditChange(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;


var
  TestForm: TTestForm;

implementation

{$R *.dfm}

procedure TTestForm.CalculateButtonClick(Sender: TObject);
begin
    if MessageDlg('Are you sure you want to calculate?', mtConfirmation, [mbYes, mbNO], 0) = mrYes  then
    begin
        try
            FindSum(StrToInt(EditOfFirstValue.Text), StrToInt(EditOfSecondValue.Text));
        except
            MessageDlg('Enter the integer number!', mtError, [mbOK], 0);
        end;
    end;
end;

procedure TTestForm.FirstEditChange(Sender: TObject);
begin
    Label3.Caption := 'Sum:'
end;

procedure TTestForm.SecondEditChange(Sender: TObject);
begin
    Label3.Caption := 'Sum:'
end;

procedure TTestForm.FindSum(A: Integer; B: Integer);
var
    Sum: Integer;

begin
    Sum := A + B;
    Label3.Caption := 'Sum: ' + IntToStr(Sum);
end;

procedure TTestForm.Open1Click(Sender: TObject);
var
    InputFile: TextFile;
    IsCorrect: Boolean;
    FirstValue: Integer;
    SecondValue: Integer;
begin
    if OpenDialog.Execute then
    begin
        IsCorrect := True;
        try
            AssignFile(InputFile, OpenDialog.FileName);
            Reset(InputFile);
        except
            MessageDlg('Input error!', mtError, [mbOK], 0);
            IsCorrect := False;
        end;
        if IsCorrect then
        begin
            try
                Readln(InputFile, FirstValue);
                Readln(InputFile, SecondValue);
                EditOfFirstValue.Text := IntToStr(FirstValue);
                EditOfSecondValue.Text := IntToStr(SecondValue);
            except
                MessageDlg('Incorrect data in the file!', mtError, [mbOK], 0);
            end;
        end;
        CloseFile(InputFile);
    end;
end;

procedure TTestForm.Save1Click(Sender: TObject);
var
    IsCorrect: Boolean;
    OutFile: TextFile;
begin
    if SaveDialog.Execute then
    begin
        IsCorrect := True;
        try
            AssignFile(OutFile, SaveDialog.FileName);
            Rewrite(OutFile);
        except
            MessageDlg('Output error!', mtError, [mbOK], 0);
            IsCorrect := False;
        end;
        if IsCorrect then
        begin
            Writeln(OutFile, Label3.Caption);
            MessageDlg('Data saved succesfully!', mtInformation, [mbOK], 0);
        end;
        CloseFile(OutFile);
    end;
end;

end.