procedure TForm1.Button1Click(Sender: TObject);
var I : Integer;
begin
    I := StrToInt(Edit1.Text);
    case I of
       1 : ShowMessage('One it is!');
       2 : ShowMessage('Two it is!');
       3 : ShowMessage('Three it is!');
       4 : ShowMessage('Four it is!');
    else
      ShowMessage('Please use a number between 1 and 4!');
    end;
end;
Type a number between 1 and 4 in Edit1, then click on Button1.