详测 Generics Collections TQueue (2): Create、Count、Clear、TrimExcess

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses Generics.Collections;

//从 TList<T> 建立 TQueue<T>
procedure TForm1.Button1Click(Sender: TObject);
var
  Queue: TQueue<string>;
  List: TList<string>;
  s,str: string;
begin
  List := TList<string>.Create();
  List.AddRange(['AA', 'BB', 'CC']);

  Queue := TQueue<string>.Create(List);

  str := '';
  for s in Queue do str := str + s + ' ';
  ShowMessage(str); {AA BB CC }

  ShowMessage(IntToStr(Queue.Count)); {3}
  Queue.Clear;
  ShowMessage(IntToStr(Queue.Count)); {0}

  //Queue.TrimExcess; { TrimExcess 方法在 Queue 好像没有存在的意义}

  List.Free;
  Queue.Free;
end;

end.