unit Unit1;

interface

uses

  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,

  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;

type

  TForm1 = class(TForm)

    Memo1: TMemo;

    Button1: TButton;

    Button2: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Form1: TForm1;

implementation

{$R *.dfm}

uses DateUtils;

procedure TForm1.Button1Click(Sender: TObject);

var

  dateList:Array of string;

  dateBetween:Integer;

  I:Integer;

  s:string;

begin

  dateBetween:=daysBetween(strtodatetime('2018/01/01'),strtodatetime('2020/02/14'));

  setlength(dateList,dateBetween+1);

  for I:=0 to dateBetween do

  begin

    s:=formatdatetime('yyyy/mm/dd',incday(strtodatetime('2018/01/01'),I));

    Memo1.Lines.Add(s);

  end;

  setlength(dateList,0);

end;

procedure TForm1.Button2Click(Sender: TObject);

var

d1,d2:TDate;

i,days:integer;

begin

Memo1.Clear;

d1:=EncodeDate(2018,1,1);

d2:=EncodeDate(2020,2,14);

days:=DaysBetween(d1,d2);

for I := 0 to days do

  begin

    Memo1.Lines.Add(FormatDateTime('yyyy-mm-dd',d1));

    d1:=d1+1;

  end;

end;

end.