unit Unit2F;

interface

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

type
    TLab1_1 = class(TForm)
        Button1: TButton;
        MainMenu: TMainMenu;
        N1: TMenuItem;
        MenuItemAboutProgram: TMenuItem;
        N3: TMenuItem;
        PopupMenu: TPopupMenu;
        EditRadius: TEdit;
        EditY: TEdit;
        EditX: TEdit;
        Result: TLabel;
        Label1: TLabel;
        Label2: TLabel;
        Label3: TLabel;
        procedure MenuItemAboutProgramClick(Sender: TObject);
        procedure EditRadiusKeyPress(Sender: TObject; var Key: Char);
        procedure EditKeyDown(Sender: TObject; var Key: Word;
          Shift: TShiftState);
        procedure Button1Click(Sender: TObject);
        procedure N3Click(Sender: TObject);
        procedure OnCloseQuery(Sender: TObject; var CanClose: Boolean);
        procedure EditChange(Sender: TObject);
        procedure EditXKeyPress(Sender: TObject; var Key: Char);
    private
        { Private declarations }
    public
        { Public declarations }
    end;

var
    Lab1_1: TLab1_1;

implementation

{$R *.dfm}

procedure TLab1_1.EditChange(Sender: TObject); // проверка на пустотут всех трех
const
    TypeError = 'Попытка ввода нечислового типа данных.';
var
    WrostInput: Boolean;
begin
    Button1.Enabled := True;
    with Sender as TEdit do
    begin
        WrostInput := False;
        try
            if (Length(EditRadius.Text) = 0) then
                Button1.Enabled := False;
            if (Length(EditRadius.Text) > 0) and (EditRadius.Text[1] = '-') then  //todo
                if (EditRadius.Text[2] = '0') then
                begin
                    Clear;
                    Button1.Enabled := False;
                end;

            if (Length(EditX.Text) = 0) then
                Button1.Enabled := False;
            if (Length(EditX.Text) = 1) and (EditX.Text[1] = '-') then
                Button1.Enabled := False;
            if (Length(EditX.Text) > 0) and (EditX.Text[1] = '-') then
                if (EditX.Text[2] = '0') then
                begin
                    Clear;
                    Button1.Enabled := False;
                end;

            if (Length(EditY.Text) = 0) then
                Button1.Enabled := False;
            if (Length(EditY.Text) = 1) and (EditY.Text[1] = '-') then
                Button1.Enabled := False;
            if (Length(EditY.Text) > 0) and (EditY.Text[1] = '-') then
                if (EditY.Text[2] = '0') then
                begin
                    Clear;
                    Button1.Enabled := False;
                end;
        except
            MessageDlg(TypeError, mtError, [mbOk], 0);
            WrostInput := True;
        end;
        if WrostInput then
        begin
            Text := '';
            Button1.Enabled := False
        end;
    end;
end;

procedure TLab1_1.Button1Click(Sender: TObject);
const
    Eps = 0.001;
    Mess = 'Поле должно быть заполненно.';
var
    X, Y, Radius: Integer;
    HypotenuseSqr: Double;
    IsLiesOnTheCircle: Boolean;
begin
    Radius := StrToInt(EditRadius.Text);
    X := StrToInt(EditX.Text);
    Y := StrToInt(EditY.Text);
    HypotenuseSqr := sqrt(X * X + Y * Y);
    if Abs(HypotenuseSqr - Radius) < Eps then
        Result.Caption := 'Точка с заданными координатами' + #13#10 +
          'лежит на окружности.'
    else
        Result.Caption := 'Точка с заданными координатами' + #13#10 +
          'не лежит на окружности.';
    Result.Visible := True;
end;

procedure TLab1_1.EditKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
var
    CurrentEdit: TEdit;
begin
    CurrentEdit := TEdit(Sender);
    if (ssShift in Shift) then
        Key := 0;
    if ((CurrentEdit.SelStart <> Length(CurrentEdit.Text)) and
      ((Key = 46) or (Key = 8))) then
        Key := 0;
end;

procedure TLab1_1.EditXKeyPress(Sender: TObject; var Key: Char);
var
    Numerals: set of Char;
begin
    with Sender as TEdit do
    begin
        if (Key = #13) and (Button1.Enabled) then
            Button1Click(Sender);
        if Length(Text) = 0 then
            Numerals := ['-', '0' .. '9', #8, #31]
        else
            Numerals := ['0' .. '9', #8, #31];
        if not(Key in Numerals) then
            Key := #0;

        if (Length(Text) > 0) and (Text[1] = '0') and (Key <> #8) then
            Key := #0;
        if (Key = #8) and (Length(Text) = 2) and (Text[1] = '-') then
            Text := '';
        if (Length(Text) > 0) and (Text[1] = '-') then
        begin
            if (Length(Text) = 3) and (Key <> #8) then
                Key := #0;
        end
        else
        begin
            if (Length(Text) = 2) and (Key <> #8) then
                Key := #0;
        end;
    end;
end;

procedure TLab1_1.EditRadiusKeyPress(Sender: TObject; var Key: Char);
var
    Numerals: set of Char;
begin
    Numerals := ['0' .. '9', #8];
    with Sender as TEdit do
    begin
        if (Key = #13) and (Button1.Enabled) then
            Button1Click(Sender);
        if not(Key in Numerals) then
            Key := #0;
        if (Length(Text) = 2) and (Key <> #8) then
            Key := #0;
        if (Length(Text) = 0) and (Key = '0') then
            Key := #0;
    end;
end;

procedure TLab1_1.MenuItemAboutProgramClick(Sender: TObject);
const
    ProgramTask =
      'Данная программа определяет находиться ли точка* на окружности.' + #13#10
      + '* Диапазон значени для радиуса (0; 100).' + #13#10 +
      '   Для координат точки (-100; 100).';
begin
    MessageDlg(ProgramTask, mtInformation, [mbOk], 0);
end;

procedure TLab1_1.N3Click(Sender: TObject);
const
    Programer =
      'Данная программа разработанa Семенцовой Критиной, студенткой 1 курса БГУИР, факультет КСИС, специальность ПОИТ.';
begin
    MessageDlg(Programer, mtInformation, [mbOk], 0);
end;

procedure TLab1_1.OnCloseQuery(Sender: TObject; var CanClose: Boolean);
const
    AreSure = 'Вы уверены, что хотите выйти?';
var
    SelectedButton: Byte;
begin
    SelectedButton := MessageDlg(AreSure, mtConfirmation, [mbYes, mbNo], 0);
    if SelectedButton <> mrYes then
        CanClose := False;
end;

end.