unit Unit2;

interface

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

type
  TFormAddElement = class(TForm)
    Label1: TLabel;
    EditAdd: TEdit;
    ButtonOK: TButton;
    procedure ButtonOKClick(Sender: TObject);
  private
  public
  end;

type
  SinglyLinkedList = class
  private
  type PNode = ^Node;   { указатель на узел }
     Node = record    { структура узла }
       element: integer; { элемент }
       next: PNode;      { ссылка на следующий }
     end;
  var Head: PNode;
  public
    constructor Create();
    procedure PushBack(Element: Integer);
    procedure AddFirst(var Head: PNode; NewNode:PNode);
  end;

var
  FormAddElement: TFormAddElement;
  Count: Integer = 1;
implementation
uses Unit1;

constructor SinglyLinkedList.Create();
begin
    new(head);
    Head := nil;
end;

procedure SinglyLinkedList.AddFirst(var Head: PNode; NewNode:PNode);
begin
    New(NewNode);
    NewNode^.next := Head;
    Head := NewNode;
end;

procedure SinglyLinkedList.PushBack(Element: Integer);
var
    NewNode: PNode;
begin
    if (Head = nil) then
    begin
        AddFirst(Head, NewNode);
    end
    else
    begin
        New(NewNode);
        NewNode := Head;
        while (NewNode^.next <> nil) do
            NewNode := NewNode.next;
        NewNode^.element := Element;
        NewNode^.next := nil;
    end;
end;

{$R *.dfm}

function IsElementCorrect(EditAdd:TEdit):Boolean;
var
    IsCorrect: Boolean;
begin
    IsCorrect := True;
    Try
        StrToInt(EditAdd.Text)
    Except
        IsCorrect := False;
        ShowMessage('sosi');
    End;
    IsElementCorrect := IsCorrect;
end;


procedure TFormAddElement.ButtonOKClick(Sender: TObject);
var
    List: SinglyLinkedList;
    Element: Integer;
begin
    if count = 1 then
        List.Create();
    if IsElementCorrect(EditAdd) then
    begin
        Element := StrToInt(EditAdd.Text);
        ListForm.StringGrid1.Cells[1,count] := EditAdd.Text;
        ListForm.StringGrid1.Cells[0,count] := IntToStr(Count);
        ListForm.StringGrid1.RowCount := ListForm.StringGrid1.RowCount + 1;
        List.PushBack(Element);
        Inc(Count);
        EditAdd.Text := '';
        FormAddElement.Close;
    end;
end;

end.