《Delphi 算法与数据结构》学习与感悟[9]: 循环链表

前面例子中, 链表的尾节点都再没有链接其他节点; 如果让尾节点再链接首节点, 不就是循环链表了吗?

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本例效果图:

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unit Unit1;

interface

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

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

var
  Form1: TForm1;

implementation

{$R *.dfm}

type
  PMyRec = ^MyRec;
  MyRec = record
    Name: string[8];
    Age : Word;
    Link: PMyRec;
  end;

var
  CurrentNode: PMyRec;

{建立链表}
procedure TForm1.FormCreate(Sender: TObject);
var
  FirstNode, EndNode: PMyRec;
begin
  New(FirstNode);
  FirstNode.Name := '李四';
  FirstNode.Age  := 44;
  FirstNode.Link := nil;
  EndNode := FirstNode;     {记住尾节点}
  CurrentNode := FirstNode;

  New(FirstNode);
  FirstNode.Name := '张三';
  FirstNode.Age  := 33;
  FirstNode.Link := CurrentNode;
  CurrentNode := FirstNode;

  New(FirstNode);
  FirstNode.Name := '钱二';
  FirstNode.Age  := 22;
  FirstNode.Link := CurrentNode;
  CurrentNode := FirstNode;

  New(FirstNode);
  FirstNode.Name := '赵一';
  FirstNode.Age  := 11;
  FirstNode.Link := CurrentNode;
  CurrentNode := FirstNode;

  EndNode.Link := FirstNode;  {把首尾接起来}
end;

{循环访问链表节点}
procedure TForm1.Button1Click(Sender: TObject);
begin
  Text := CurrentNode.Name + #44 + IntToStr(CurrentNode.Age);
  CurrentNode := CurrentNode.Link;
end;

end.