以Delphi 實作Queue 類別，含範例

發表時間：2003-03-16 00:01:58

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據 superlevin 版主告之，有個Queue 的需求，我便實作了一個TQueue 在此野人獻曝一番，僅用到簡單的動態陣列，實現環型佇列若程式有誤尚請資料結構之高手多多指教有興趣研究的朋友，也可以改成串列佇列或是以指標來實現或是加入其它檢查

    unit Unit1;    interface    uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;    type
  TForm1 = class(TForm)
    Button1: TButton;
    ListBox1: TListBox;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
//--------------------宣告TQueue -----------------------------------
type
  TQueue = class
  private
    FBuffer :array of Variant;  //以陣列當Buffer
    FBufferSize :Integer;  //記錄buffer大小
    FPosition :Integer;   //指向目前欲取出的項目位置
    FIndex    :Integer;   //目前資料的位置
  public
    procedure Push(iData:Variant);
    Function Pop():Variant ;
    procedure SetBuffer(iSize:Integer); //設定buffer 大小
    property BufferSize :Integer read FBufferSize Write SetBuffer; //屬性
  end;        var
  Form1: TForm1;    implementation    {$R *.dfm}    procedure TQueue.Push(iData:Variant);
begin
    FBuffer[FIndex]:=iData; //寫入資料
    Inc(FIndex);  //index 下移
    FIndex :=FIndex mod FBufferSize ; //若已到底則重頭開始
end;    function TQueue.Pop():Variant ;
begin
    Result:=FBuffer[FPosition]; //讀出資料
    Inc(FPosition); //Position 下移
    FPosition :=FPosition mod FBufferSize ;   //若已到底則重頭開始
end;    procedure TQueue.SetBuffer(iSize:Integer);
begin
    SetLength (FBuffer,iSize);  //Buffer 初始
    FIndex :=0;
    FPosition :=0;
    FBufferSize:=iSize;  //傳回buffer size
end;
procedure TForm1.Button1Click(Sender: TObject);
var
    q :TQueue ;
begin
    q:=TQueue.Create ;   //建立TQueue 物件
    q.SetBuffer (5);
    q.Push ('a');
    q.Push('b');
    q.Push('c');
    q.Push(4);
    q.Push(5);
    ListBox1.Items.Add (q.Pop )  ;
    ListBox1.Items.Add (q.Pop )  ;
    ListBox1.Items.Add (q.Pop )  ;
    ListBox1.Items.Add (q.Pop )  ;
    ListBox1.Items.Add (q.Pop )  ;
    ListBox1.Items.Add (q.Pop )  ;
    ListBox1.Items.Add (q.Pop )  ;
    ListBox1.Items.Add (q.Pop )  ;        self.Caption :=IntToStr( q.BufferSize);   //取得Buffer 大小
    q.Free ; //釋放TQueue
end;    end.

========以下程式碼同上，供直接複製使用========================= unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TForm1 = class(TForm) Button1: TButton; ListBox1: TListBox; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; //--------------------宣告TQueue ----------------------------------- type TQueue = class private FBuffer :array of Variant; //以陣列當Buffer FBufferSize :Integer; //記錄buffer大小 FPosition :Integer; //指向目前欲取出的項目位置 FIndex :Integer; //目前資料的位置 public procedure Push(iData:Variant); Function Pop():Variant ; procedure SetBuffer(iSize:Integer); //設定buffer 大小 property BufferSize :Integer read FBufferSize Write SetBuffer; //屬性 end; var Form1: TForm1; implementation {$R *.dfm} procedure TQueue.Push(iData:Variant); begin FBuffer[FIndex]:=iData; //寫入資料 Inc(FIndex); //index 下移 FIndex :=FIndex mod FBufferSize ; //若已到底則重頭開始 end; function TQueue.Pop():Variant ; begin Result:=FBuffer[FPosition]; //讀出資料 Inc(FPosition); //Position 下移 FPosition :=FPosition mod FBufferSize ; //若已到底則重頭開始 end; procedure TQueue.SetBuffer(iSize:Integer); begin SetLength (FBuffer,iSize); //Buffer 初始 FIndex :=0; FPosition :=0; FBufferSize:=iSize; //傳回buffer size end; procedure TForm1.Button1Click(Sender: TObject); var q :TQueue ; begin q:=TQueue.Create ; //建立TQueue 物件 q.SetBuffer (5); q.Push ('a'); q.Push('b'); q.Push('c'); q.Push(4); q.Push(5); ListBox1.Items.Add (q.Pop ) ; ListBox1.Items.Add (q.Pop ) ; ListBox1.Items.Add (q.Pop ) ; ListBox1.Items.Add (q.Pop ) ; ListBox1.Items.Add (q.Pop ) ; ListBox1.Items.Add (q.Pop ) ; ListBox1.Items.Add (q.Pop ) ; ListBox1.Items.Add (q.Pop ) ; self.Caption :=IntToStr( q.BufferSize); //取得Buffer 大小 q.Free ; //釋放TQueue end; end.