TQueue 和 TStack, 一个是队列列表, 一个是堆栈列表; 一个是先进先出, 一个是先进后出.
TQueue 主要有三个方法、一个属性:
Enqueue(入列)、Dequeue(出列)、Peek(查看下一个要出列的元素);
Count(元素总数).
本例效果图:
代码文件:
TQueue 主要有三个方法、一个属性:
Enqueue(入列)、Dequeue(出列)、Peek(查看下一个要出列的元素);
Count(元素总数).
本例效果图:
代码文件:
unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TForm1 = class(TForm) Memo1: TMemo; Button1: TButton; Button2: TButton; Button3: TButton; procedure FormCreate(Sender: TObject); procedure FormDestroy(Sender: TObject); procedure Button1Click(Sender: TObject); procedure Button2Click(Sender: TObject); procedure Button3Click(Sender: TObject); end; var Form1: TForm1; implementation {$R *.dfm} uses Generics.Collections; {Delphi 2009 新增的泛型容器单元} type TRec = record Name: string; Age: Word; end; var Queue: TQueue<TRec>; {定义一个泛型 TQueue 类, 这指定了要用于上面定义的 TRec 记录} {建立} procedure TForm1.FormCreate(Sender: TObject); begin Queue := TQueue<TRec>.Create; Memo1.Clear; Button1.Caption := Button1.Caption + ' 入列'; Button2.Caption := Button2.Caption + ' 出列'; Button3.Caption := Button3.Caption + ' 下一个出列的...'; end; {释放} procedure TForm1.FormDestroy(Sender: TObject); begin Queue.Free; end; {入列: Enqueue} procedure TForm1.Button1Click(Sender: TObject); var rec: TRec; begin rec.Name := StringOfChar(Char(65 + Random(26)), 3); rec.Age := Random(150); Queue.Enqueue(rec); Text := Format('当前队列成员总数: %d', [Queue.Count]); {让 Memo1 配合显示} Memo1.Lines.Add(Format('%s, %d', [rec.Name, rec.Age])); end; {出列: Dequeue} procedure TForm1.Button2Click(Sender: TObject); var rec: TRec; begin if Queue.Count = 0 then Exit; rec := Queue.Dequeue; ShowMessage(Format('%s, %d', [rec.Name, rec.Age])); Text := Format('当前队列成员总数: %d', [Queue.Count]); {让 Memo1 配合显示} Memo1.Lines.Delete(0); end; {下一个出列的元素: Peek} procedure TForm1.Button3Click(Sender: TObject); var rec: TRec; begin if Queue.Count = 0 then Exit; rec := Queue.Peek; ShowMessage(Format('%s, %d', [rec.Name, rec.Age])); end; end.窗体文件:
object Form1: TForm1 Left = 0 Top = 0 Caption = 'Form1' ClientHeight = 147 ClientWidth = 284 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'Tahoma' Font.Style = [] OldCreateOrder = False Position = poDesktopCenter OnCreate = FormCreate OnDestroy = FormDestroy PixelsPerInch = 96 TextHeight = 13 object Memo1: TMemo Left = 0 Top = 0 Width = 121 Height = 147 Align = alLeft Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -13 Font.Name = 'Courier New' Font.Style = [] Lines.Strings = ( 'Memo1') ParentFont = False ScrollBars = ssBoth TabOrder = 0 ExplicitHeight = 201 end object Button1: TButton Left = 127 Top = 21 Width = 146 Height = 25 Caption = 'Button1' TabOrder = 1 OnClick = Button1Click end object Button2: TButton Left = 127 Top = 61 Width = 146 Height = 25 Caption = 'Button2' TabOrder = 2 OnClick = Button2Click end object Button3: TButton Left = 127 Top = 99 Width = 146 Height = 25 Caption = 'Button3' TabOrder = 3 OnClick = Button3Click end end