求教:用指针构建链表的程序注释 ( 积分: 50 )

temarg · 2007-05-04

在学习指针类型中,基本概念总搞不清楚,以致看不懂基本的程序.现将一个示例程序附后,请各位朋友给出详细注释(主要是实现部分的四个过程)为本人解惑. 清单如下,请给出详细注释.原有注释可作为参考. unit zhizhen01Unit1; interface uses   Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,   Dialogs, StdCtrls; type   TLinkExam = class(TForm)     ListBox1: TListBox;     Edit1: TEdit;     Label1: TLabel;     Label2: TLabel;     BtnList: TButton;     BtnDel: TButton;     BtnQuit: TButton;     Label3: TLabel;     Button1: TButton;     procedure Edit1KeyPress(Sender: TObject; var Key: Char);     procedure FormCreate(Sender: TObject);     procedure BtnListClick(Sender: TObject);     procedure BtnDelClick(Sender: TObject);     procedure BtnQuitClick(Sender: TObject);   private     { Private declarations }   public     { Public declarations }   end; var   LinkExam: TLinkExam; implementation {$R *.dfm}   type   PLink=^Node;   Node=Record   Data:string[30];   Next

Link;   end;   var   DtRec

Link; procedure TLinkExam.FormCreate(Sender: TObject);   begin   DtRec:=NIL;   end; procedure TLinkExam.Edit1KeyPress(Sender: TObject; var Key: Char); var tempP,P

Link; begin     if key=#13 then  //如果按下回车键     begin  new(tempP);         //创建一个节点  tempP^.Data:=Edit1.Text;  tempP^.Next:=NIL;  IF DtRec=NIL Then    //如果链表为空    begin    New(DtRec);        //创建链表    DtRec:=tempP;    end        Else                    //如果链表不为空        begin        p:=DtRec;        while p^.Next<>NIL do   //找表尾        P:=P^.Next;        p^.next:=tempP;         //将新结点添加到表尾        end;    edit1.Clear;    edit1.SetFocus;     end; end; procedure TLinkExam.BtnListClick(Sender: TObject); var p

link; begin  listBox1.Clear;  p:=DtRec;  repeat  listBox1.Items.Add(P^.Data);  P:=P^.Next;  until P=Nil;   end; procedure TLinkExam.BtnDelClick(Sender: TObject); var p,P1

link; i:integer; begin   i:=0;   p:=DtRec;   if P=NIL then   //如果链表为空表   showmessage('链表为空表!')     else          // 如果不为空表     if P^.Data=Edit1.Text then  {如果链表的第一个节点     为要删除的节点}     begin     DtRec:=P^.Next;     P^.Next:=NIL;     P:=dtRec;     end     else  {如果第一个节点不是要删除的节点}   begin     p1:=p^.Next;     if p1<>NIL then     repeat   if p1.Data=edit1.Text then //如果找到了一个要删除的节点       begin       p^.Next:=p1^.Next;       p1:=p;       i:=i+1;       end           else         begin         p:=p1;         p1:=p1^.Next;         end     until p1=NIL;     if i=0 then   {如果链表不存在要删除的节点}     showmessage('无匹配的数据');   end;   edit1.clear;   Edit1.SetFocus ; end; procedure TLinkExam.BtnQuitClick(Sender: TObject); begin close; end; end.

hsgrass · 2007-05-04

多看几本不同出版社的<数据结构>就懂啦,这个钱不能省的 它们的描述不一样,不过都是说同一件事,总有一种描述适合你滴, 或者上网看看别人推荐的, 祝你成功!

我爱大咪咪 · 2007-05-04

感觉一目了然,LZ有哪些地方不懂??

linuxping · 2007-05-04

一目了然 unit untDict; interface uses SysUtils,StrUtils, Variants, Classes,Dialogs; const Words='words.txt'; //字典文件名 //链表元素 type PChainElem=^ChainElem; ChainElem=record      value

ointer;          //指向一个TCharTreeNode      sucElem

ChainElem;     //后继节点指针(即：子树根节点及其兄弟节点) end; //链表类 type TChain=class      private         head,tail

ChainElem;      published         constructor create;         destructor destroy;override;         procedure ApendElem(curElem

ChainElem); //在链表尾追加一个节点         function GetNext(curElem

ChainElem)

ChainElem;   //返回当前节点的下一个节点（兄弟）        { property ChainHead

ointer read GetHead write SetChainHead default nil; //头节点为空，说明是叶子了。（父节点）}         function GetHead

ChainElem; //获得表头节点 end; //树节点 type TCharTreeNode=class{(TChain)}      private         sValue:Word;//保存汉字的索引，通过该值可以计算出汉字的机内码，从而还原成汉字         WordEnd:Boolean;  //成词标记         WordFreq:Word; //词频         Chain:TChain;     //儿子节点组成的链表         ParentNode:TCharTreeNode; //父节点指针         function  GetCharacter:string;         procedure SetCharacter(s:String);         procedure SetWordEnd(V:boolean);         procedure SetWordFreq(AFreq:Word);      published         constructor create;         destructor destroy;override;         function AddChild(const character:string;wFreq:longint=0;Wordend:Boolean=false):TCharTreeNode;  //         function GetFirstChild:TCharTreeNode; //第一个孩子节点         function GetFirstElem

ChainElem;         function GetNextSibling(Elem

ChainElem):TCharTreeNode; //获得兄弟节点指针}         function GetNextElem(Elem

ChainElem)

ChainElem;         property Character:string read  GetCharacter write SetCharacter ;         property IsWordEnd:Boolean read wordEnd write SetWordEnd default false;         property WordFreqs:Word  read WordFreq write SetWordFreq default 1;                  function GetParent:TCharTreeNode;  //获得父节点指针         function GetHead

ChainElem; end; //树 type TCharTree=class      private         root:array[Word] of TCharTreeNode;         NodeCount:LongWord;      //节点个数         procedure setCount(V:LongWord);         procedure FreeAllNode(Node:TCharTreeNode);     public         constructor create;         destructor destroy;override;      published         property Count:LongWord read NodeCount write SetCount;         function GetRoot(i:Word):TCharTreeNode; end; //数据库的数据载入到树---字典类 type TDictType=(dtOrder,dtReveser); type  PFreqAndWord=^TFreqAndWord;       TFreqAndWord=record          iFreq,          iLen:Integer;       end; type TArrayString=array[0..249]of TFreqAndWord;      TArrayBool=array[0..249]of Boolean;      PArrayString=^TArrayString;      PArrayBool=^TArrayBool; type TInterfacedDict=class(TInterfacedobject)      private        FTree:TCharTree;        FDictType:TDictType;        FDictPath:string;        function NodesCount:LongWord;        procedure SetNodeCount(ACount:LongWord);     protected        procedure SetDictType(AType:TDictType);        procedure SetDictPath(Apath:string);      public        class function ChangeDict(APath:string):TInterfacedDict;virtual; //切换字典        class function PlusDict(APath:string):TInterfacedDict;virtual;        function FindCharacter(S:AnsiString;nd:TCharTreeNode=nil):TCharTreeNode;//若nd=nil,则是查找根节点。否则，在nd的儿子里查找        //function FindWordInDict(S: string): TCharTreeNode;virtual;  //S是否是一个词        function  Trace(node1:TCharTreeNode):string;virtual; //没有匹配到，则须向上回溯        function  TraceAll(node1:TCharTreeNode;var FItem:TArrayString):Integer;virtual; //没有匹配到，则须向上回溯(找出路径上所有可以成词的词)        function GetRoot(i:word):TCharTreeNode;overload;        function GetRoot(c:AnsiString):TCharTreeNode;overload;        function GetFreq(var nd:TCharTreeNode):word;virtual;        function GetFee(nd:TCharTreeNode):word;virtual;        constructor create;        destructor Destroy;override;        procedure LoadDict(APath: string);virtual;    //载入不同的字典--->由子类去实现。        property Tree:TCharTree read FTree write FTree;        property Count:LongWord read NodesCount write SetNodeCount;        property DictType:TDictType read FDictType {write SetDictType};  //只读        property DictPath:string  read FDictPath write SetDictPath;     procedure AfterConstruction; override; end; type TDict=class(TInterfacedDict)  //单例类      private              published        procedure LoadDict(APath: string);override;      public        class function GetInstance(chooce:Integer):TDict;        constructor Create(APath: string);        class function CreateInstance(APath:string):Tdict; //创建单例类        class function ChangeDict(APath:string):TInterfacedDict;override;        class function PlusDict(APath:string):TInterfacedDict; override;                procedure ReleaseInstance; //释放单例类        destructor Destroy;override; end; type TReverseDict=class(TInterfacedDict) //逆序载入字典，供逆向最大匹配使用      published        procedure LoadDict(APath: string);override;      public        class function GetInstance(chooce:Integer):TReverseDict;        constructor Create(APath: string);        class function CreateInstance(APath:string):TReverseDict; //创建单例类        class function ChangeDict(APath:string):TInterfacedDict;override;        class function PlusDict(APath:string):TInterfacedDict;override;        procedure ReleaseInstance; //释放单例类        destructor Destroy;override; end; var   DictInstance:TDict;          {正序字典和逆序字典的实例}   RevDictInstance:TReverseDict; implementation uses untConst{,IniOp}; var    iDictRefCount,iRevDictRefCount:Integer; {字典的引用计数}    { TChain } procedure TChain.ApendElem(curElem: PChainElem); {var   curPointer

ChainElem;} begin       if Self.head=nil then       begin          head:=curElem;          tail:=curElem;          Exit;       end;       tail.sucElem:=curElem;       tail:=curElem; end; constructor TChain.create; begin   head:=nil;   tail:=nil; end; destructor TChain.destroy; var   Pcur,Pnext

ChainElem; begin   Pcur:=head;   while (Pcur<>nil) do   begin         pNext:=pCur^.sucElem;         if Pcur^.value<>nil then         begin           TCharTreeNode(Pcur^.value).Free;           Dispose(pCur);         end;         pCur:=pNext;   end;   inherited; end; function TChain.GetHead

ChainElem; begin       Result:=head; end; function TChain.GetNext(curElem: PChainElem): PChainElem; begin    Result:=curElem^.sucElem; end; { TCharTreeNode } function TCharTreeNode.AddChild(const character: string;wFreq:longint;Wordend:Boolean):TCharTreeNode; var   tn:TCharTreeNode;   ChainItem

ChainElem; begin      tn:=TCharTreeNode.create;      tn.sValue:=word(byte(character[1]) shl 8) + word(character[2]);      tn.WordEnd:=Wordend;      tn.WordFreq:=wFreq;      tn.ParentNode:=Self;      New(ChainItem);      ChainItem^.value:=pointer(tn);  ///      ChainItem^.sucElem:=nil;      Self.Chain.ApendElem(ChainItem);  //加入到儿子链表中      Result:=tn; end; constructor TCharTreeNode.create; begin     Chain:=TChain.create;     ParentNode:=nil; end; destructor TCharTreeNode.destroy; begin   Chain.destroy;   inherited; end; function TCharTreeNode.GetCharacter: string; {var  //S:string;  preByte,sucByte:Byte;} begin   SetLength(Result,2);   Result[1]:=Char(Byte((sValue and 65280) shr 8));   Result[2]:=Char(Byte(sValue and 255)); end; function TCharTreeNode.GetFirstChild: TCharTreeNode;          //获得第一个孩子节点 begin    if Assigned(Chain.GetHead.value) then       Result:= TCharTreeNode(Chain.GetHead.value)    else       Result:=nil; end; function TCharTreeNode.GetParent: TCharTreeNode; begin       result:=Self.ParentNode; end; function TCharTreeNode.GetNextSibling(Elem

ChainElem): TCharTreeNode;   //获得当前节点的兄弟 begin                                   //参数为 当前节点所在的PChainElem    if Elem.sucElem<>nil then       result:= TCharTreeNode(Elem.sucElem.value)    else       Result:=nil; end; procedure TCharTreeNode.SetCharacter(s: String); begin   sValue:=word(Byte(S[1]) shl 8) +word(Byte(s[2])); end; procedure TCharTreeNode.SetWordEnd(V: boolean); begin    WordEnd:=V; end; function TCharTreeNode.GetNextElem(Elem: PChainElem): PChainElem; begin    Result:=Elem.sucElem; end; function TCharTreeNode.GetFirstElem: PChainElem; begin    Result:=Self.Chain.GetHead; end; function TCharTreeNode.GetHead: PChainElem; begin Result:=Chain.head; end; procedure TCharTreeNode.SetWordFreq(AFreq: Word); begin   WordFreq:=AFreq; end; { TCharTree } constructor TCharTree.create; var   I:Word; begin  for i:=0 to 65535 do     //根  begin     root:=TCharTreeNode.create;     root.sValue:=i;     root.WordEnd:=False;  //默认不是单字词           end;  NodeCount:=65536; end; destructor TCharTree.destroy; var   i:Word; begin   //做树的遍历，释放每一个节点   for i:=0 to 65535 do       FreeAllNode(root);   inherited; end; procedure TCharTree.FreeAllNode(Node:TCharTreeNode); var   Vointer; begin     if Node=nil then Exit;     if (Node.Chain=nil)  then     begin       Node.Free;       Exit;     end;      if (Node.GetHead=nil) then     begin       Node.Free;       Exit;     end;     if Node.GetHead.value<>nil then   //如果它还有儿子节点，     begin         V:=Node.GetHead.value;         Node.Chain.head:=Node.GetHead.sucElem;         FreeAllNode(TCharTreeNode(V));     end     else         TCharTreeNode(V).Free; end; function TCharTree.GetRoot(i: Word): TCharTreeNode; begin   Result:=root; end; procedure TCharTree.setCount(v:LongWord); begin    NodeCount:=v; end; { TDict } class function TDict.ChangeDict(APath: string): TInterfacedDict; begin    if Assigned(TDict.GetInstance(0)) then    begin      if TDict.GetInstance(0).DictPath=Trim(APath) then  //字典相同      begin         Result:=TDict.GetInstance(0);         Exit;      end      else         TDict.GetInstance(0).ReleaseInstance;  //字典不同,则释放以前字典,并重新加载新字典    end;    Result:=TDict.CreateInstance(APath);    try       Result.LoadDict(APath);    except      {$Message Hint 'show some error information abort Dict'}      Abort;    end; end; constructor TDict.Create(APath: string); begin //  inherited Create; //  LoadDict(APath+words);   raise Exception.CreateFmt(StrCreateError,[ClassName]); end; class function TDict.CreateInstance(APath: string):TDict; begin      Result:=GetInstance(1);   //LoadDict(APath+words); end; destructor TDict.Destroy; begin   if GetInstance(0)=Self then GetInstance(2);   inherited; end; class function TDict.GetInstance(chooce: Integer): TDict; //const instance:TDict=nil; begin   case chooce of   0: ;   //供释放使用   1:                 //创建       begin         Inc(iDictRefCount,1);         if not Assigned(DictInstance) then         begin           DictInstance:=inherited Create;           //LoadDict(APath+words);         end ;       end;   2:  DictInstance:=nil;  //赋值   else       raise Exception.CreateFmt(strCreateParamError,[ClassName]);   end;      Result:=DictInstance; end; procedure TDict.LoadDict(APath: string); var   nd,tmpNode:TCharTreeNode;   str:string;   index:Word;   i,j:LongWord;   {ItemChainElem; }   {isExsit:Boolean;}   F:TextFile;   PosDel1,PosDel2:Integer;   wfreq:string;   lst:TStringList;   sTip:string;   procedure Split(Splitor,Str:string); //sSubstr分割sStr,存入TStringList.   var     PSplitor,PStr,PPosAnsiChar;     s:string;   begin     PSplitor:=PAnsiChar(Splitor);     PStr:=PAnsiChar(Str);     PPos:=PAnsiChar(Str);     while PPos<>#0 do     begin         while (PPos^<>PSplitor^) and (PPos^<>#0) do inc(PPos);         SetString(S,PStr,PPos-PStr);         lst.Add(S);         if PPos^<>#0 then inc(PPos)         else break;         pstr:=ppos;     end;   end; begin    SetDictType(dtOrder);   //指定字典属性    FDictPath:=APath;    lst:=TStringList.Create;    try       AssignFile(F,Apath);       try         Reset(F);       except          MessageDlg((Format(StrFileNotFound,[APath])),mtWarning,[mbOK],0);          Abort;       end;       try         while (not Eof(F)) do  //把每一个词加载到树上         begin           Readln(F,str);  //在字典中取词           sTip:=str;           Split(#9,str);               {格式如: 22072 "分段" 5}           str:=lst.Strings[1];           PosDel1:=Pos('"',str);      {如果是汉字,则左右两侧有双引号,去掉双引号}           PosDel2:=LastDelimiter('"',str);           str:=Copy(str,PosDel1+1 ,PosDel2-PosDel1-1); //剔除双引号           if lst.Count>=3 then               wfreq:=lst.Strings[2];           lst.Clear;           if Length(str)<=1 then Continue; //不是汉字(应该不会出现)           try           index:=word(Byte(str[1]) shl 8)+ word(Byte(str[2]));  //树根节点索引           except             MessageDlg(Format(StrRowError,[sTip]),mtWarning,[mbOK],0);             Halt;           end;           nd:=Tree.root[index];           if Length(str)=2 then  //单字词           begin               nd.WordFreq:=nd.WordFreq+StrToInt(wFreq);               nd.WordEnd:=True;               continue ;           end;           for i:=1 to (Length(str)  div 2)-1  do           begin               tmpNode:=FindCharacter(Copy(str,i*2+1,2),nd);               if tmpNode=nil then                   nd:=nd.AddChild(Copy(str,i*2+1,2)) //值相等的节点不存在。追加。               else               begin                   nd:=tmpNode;                   Continue;               end;               Tree.Count:=tree.count+1;     //树节点个数加1           end;  //end 'for'           nd.WordFreq:=StrToIntdef(wfreq,1);   //词频           nd.WordEnd:=True;  //词结束标记         end;        except           MessageDlg(StrLoadDictError,mtInformation,[MBOK],0);           Abort;        end;       finally           lst.Free;           CloseFile(F);       end; end; class function TDict.PlusDict(APath: string): TInterfacedDict; begin   { if Assigned(TDict.GetInstance(0)) then    begin       TDict(TDict.GetInstance(0))    end; } end; procedure TDict.ReleaseInstance; begin   Dec(iDictRefCount,1);   if iDictRefCount>0 then Exit;     if GetInstance(0)<>nil then       GetInstance(0).Free; end; { TInterfacedDict } procedure TInterfacedDict.AfterConstruction; begin   inherited;   // end; class function TInterfacedDict.ChangeDict(APath: string): TInterfacedDict; begin     //空. 须被覆盖.本想使用Virtui+Abstract修饰,但抽象类不能创建实例.    //下同. end; constructor TInterfacedDict.Create; begin   inherited;   FTree:=TCharTree.Create; end; destructor TInterfacedDict.Destroy; begin   FreeAndNil(FTree);   inherited; end; function TInterfacedDict.FindCharacter(S: AnsiString;   nd: TCharTreeNode): TCharTreeNode; var                        //查找nd的子节点中值为S的节点。若找到了，则返回该子节点，否则返回nil   ItemChainElem;         //若nd 缺省，则返回值为S的根节点 begin    if nd=nil then    //返回根节点       Result:=GetRoot(S)       //Result:=GetRoot(word(Byte(S[1]) shl 8) +word(byte(s[2])))    else    begin       item:=nd.GetHead;       while(item<>nil) do       begin           if (TCharTreeNode(item.value)).Character=s then //找到值相等的儿子节点           begin             Result:= TCharTreeNode(item.value);             Exit;           end           else               item:=item.sucElem;       end;       Result:=nil;   end; end; function TInterfacedDict.GetFee(nd: TCharTreeNode): word; begin    // end; function TInterfacedDict.GetFreq(var nd: TCharTreeNode): word; begin     Result:=nd.WordFreq; end; function TInterfacedDict.GetRoot(i:word):TCharTreeNode; begin    Result:=Tree.GetRoot(i); end; function TInterfacedDict.GetRoot(c: AnsiString): TCharTreeNode; var   wIndex:word; begin    wIndex:=Word(byte(c[1]) shl 8) + Word(c[2]);    //if FTree=nil then ShowMessage('tree nil');    Result:=Tree.GetRoot(wIndex); end; procedure TInterfacedDict.LoadDict(APath: string); begin   // end; function TInterfacedDict.NodesCount: LongWord; begin    Result:=Tree.NodeCount; end; class function TInterfacedDict.PlusDict(APath: string): TInterfacedDict; begin   // end; procedure TInterfacedDict.SetDictPath(Apath: string); begin    FDictPath:=Apath; end; procedure TInterfacedDict.SetDictType(AType: TDictType); begin   FDictType:=AType; end; procedure TInterfacedDict.SetNodeCount(ACount: LongWord); begin    Tree.NodeCount:=ACount; end; function TInterfacedDict.Trace(node1: TCharTreeNode): string; var   isStart:Boolean;   nd:TCharTreeNode; begin   isStart:=False;   Result:='';   if  node1=nil then raise Exception.Create('Trace错误!');   //如果node1=nil 可能出现死循环   repeat      if node1.IsWordEnd then isStart:=True;      if isStart  then Result:=node1.Character+Result; //分词结果      nd:=node1.GetParent;      if nd=nil then  Break;     {回溯到了根节点}      node1:=nd;   until (false);  //回溯 end; function TInterfacedDict.TraceAll(node1: TCharTreeNode;var FItem:TArrayString):Integer; var   nd:TCharTreeNode;   bItem:TArrayBool;   i,j:Integer; begin   if  node1=nil then raise Exception.CreateFmt(StrNotAssignedError,[node1.ClassName]); //如果node1=nil 可能出现死循环   FillChar(FItem,SizeOf(TArrayString),0);   i:=0;   repeat      if node1.IsWordEnd then      begin        bItem:=True;        FItem.iFreq:=node1.WordFreqs;        Inc(i);      end;      if i>10 then raise Exception.Create(StrOverBoundsError);            for j:=0 to i-1 do         if bItem[j] then             FItem[j].iLen:=FItem[j].iLen+Length(node1.Character);  //长度计数      nd:=node1.GetParent;            if nd=nil then  Break;     {回溯到了根节点}      node1:=nd;   until (false);  //回溯   result:=i;  //左临词的个数 end; { TReverseDict } class function TReverseDict.ChangeDict(APath: string): TInterfacedDict; begin    if Assigned(TReverseDict.GetInstance(0)) then    begin      if TReverseDict.GetInstance(0).DictPath=Trim(APath) then  //字典相同      begin         Result:=TReverseDict.GetInstance(0);         Exit;      end      else         TReverseDict.GetInstance(0).ReleaseInstance;  //字典不同,则释放以前字典,并重新加载新字典    end;    Result:=TReverseDict.CreateInstance(APath);    Result.LoadDict(APath); end; constructor TReverseDict.Create(APath: string); begin   raise Exception.CreateFmt(StrCreateError,[ClassName]); end; class function TReverseDict.CreateInstance(APath: string):TReverseDict; begin      Result:=GetInstance(1);   //LoadDict(APath+words); end; destructor TReverseDict.Destroy; begin     if GetInstance(0)=Self then GetInstance(2);     inherited; end; class function TReverseDict.GetInstance(chooce: Integer): TReverseDict; //const instance:TDict=nil; begin   case chooce of   0: ;   //供释放使用   1:                 //创建       begin         Inc(iRevDictRefCount,1);         if not Assigned(RevDictInstance) then         begin           RevDictInstance:=inherited Create;           //LoadDict(APath+words);         end ;       end;   2:RevDictInstance:=nil;   else     raise Exception.CreateFmt(strCreateParamError,[ClassName]);   end;      Result:=RevDictInstance; end; procedure TReverseDict.LoadDict(APath: string);    //载入字典 var nd,tmpNode:TCharTreeNode; str:string; index:Word; i,j:LongWord; {ItemChainElem; } {isExsit:Boolean;} F:TextFile; PosDel1,PosDel2:Integer; wfreq:string; lst:TStringList; sTip:string;   procedure Split(Splitor,Str:string); //sSubstr分割sStr,存入TStringList.   var     PSplitor,PStr,PPosChar;     s:string;   begin     PSplitor:=PChar(Splitor);     PStr:=PChar(Str);     PPos:=PChar(Str);     while PPos<>#0 do     begin         while (PPos^<>PSplitor^) and (PPos^<>#0) do inc(PPos);         SetString(S,PStr,PPos-PStr);         lst.Add(S);         if PPos^<>#0 then inc(PPos)         else break;         pstr:=ppos;     end;   end; begin    FDictPath:=APath;    SetDictType(dtReveser);   //指定字典属性    lst:=TStringList.Create;    try       AssignFile(F,Apath);       Reset(F);       try         while (not Eof(F)) do  //把每一个词加载到树上         begin           Readln(F,str);  //在字典中取词           sTip:=str;                      Split(#9,str);           str:=lst.Strings[1];           PosDel1:=Pos('"',str);           PosDel2:=LastDelimiter('"',str);           str:=Copy(str,PosDel1+1 ,PosDel2-PosDel1-1); //剔除双引号 ,找到词           if lst.Count>=3 then       //词频               wfreq:=lst.Strings[2];           lst.Clear;           if Length(Trim(str))<=1 then Continue; //不是汉字(应该不会出现)           str:=AnsiReverseString(Trim(str)); //逆序           try           index:=word(Byte(str[1]) shl 8)+ word(Byte(str[2]));  //树根节点索引           except             MessageDlg(Format(StrRowError,[sTip]),mtWarning,[mbOK],0);             Halt;           end;           nd:=Tree.root[index];           if Length(str)=2 then    //单字词           begin               nd.WordFreq:=StrToIntDef(wFreq,1);               nd.WordEnd:=True;               continue ;           end;           for i:=1 to (Length(str)  div 2)-1  do           begin               tmpNode:=FindCharacter(Copy(str,i*2+1,2),nd);               if tmpNode=nil then                   nd:=nd.AddChild(Copy(str,i*2+1,2)) //值相等的节点不存在。追加。               else               begin                   nd:=tmpNode;                   Continue;               end;               Tree.Count:=tree.count+1;     //树节点个数加1           end;  //end 'for'           nd.WordFreq:=StrToIntdef(wfreq,1);   //词频           nd.WordEnd:=True;  //词结束标记         end;        except           MessageDlg(StrLoadDictError,mtInformation,[MBOK],0);           Abort;        end;       finally           CloseFile(F);       end; end; class function TReverseDict.PlusDict(APath: string): TInterfacedDict; begin end; procedure TReverseDict.ReleaseInstance; begin   Dec(iRevDictRefCount,1);   if iRevDictRefCount<=0 then     if GetInstance(0)<>nil then           GetInstance(0).Free; end; initialization   DictInstance:=nil;   RevDictInstance:=nil;   iRevDictRefCount:=0;   iDictRefCount:=0; finalization   //... end.

temarg · 2007-05-04

linuxping兄贴的代码太长了,本人还是看不懂. 我只想弄懂最基本的知识,不清楚的地方如下,烦请各位解释: 主要是

rodedure TLindExit1KeyPress(sender:var Key:char); 请自 if DtRec=NIL then 始至本段程序添加完表尾,本人都不清楚程序的意义,请解释.

linuxping · 2007-05-05

DtRec代表一个链表，但它指向链表的表头，它为nil，链表就什么也没有。

flowoverstone · 2007-05-06

关键问题是楼主“数据结构”功底差，建议你好好读几本这方面的书，有个系统的了解。否则即使别人给你解释了一个问题下次还会有其它问题出现。

jainibunan · 2007-05-06

这个不难的，楼上的都说过了，如果你不明白整个数据结构，基础不扎实，就是懂了这个，要是一变化，你就又不懂了，所以别对这些代码耿耿于怀，不要急，先回去把相关的基础知识看懂，到时候你再回来看这题，就会发现 just that！学习需要耐心哦，加油！

temarg · 2007-05-07

感谢朋友们的热情解答.散分,不多,请笑纳.

求教:用指针构建链表的程序注释 ( 积分: 50 )

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