下面图老师小编跟大家分享自己编写树(Tree)的封装类，一起来学习下过程究竟如何进行吧！喜欢就赶紧收藏起来哦~
在VCL中包含有一个TList类，几乎可以实现链表所有功能，Delphi的工程师真是伟大。但是在实际应用中需要TTree类，来实现树的功能，我写了两个类TyuTree，TYuNode。可以方便实现，树创建，结点增删、移动功能。请大家指教。代码实例：Procedure Test();Var YuTree: TyuTree;Node: TYuNode;Begin //第1步：创建树、增加第一个结点0YuTree := TYuTree.Create;Node := YuTree.Add(nil);//nil,表示增加根结点Node.Data := Pointer(0); //第2步：在结点0下增加子结点1Node := YuTree.AddChild(Node);Node指向结点0Node.Data := Pointer(1); //第3步：在结点1下增加子结点2Node := YuTree.AddChild(Node);Node.Data := Pointer(2); //第4步：切换到结点2的父结点1Node := Node.GetParent; //第5步：在结点1下增加子结点3，并作为第1个子结点Node := YuTree.AddChildFirst(Node);Node.Data := Pointer(3);
（本文来源于图老师网站，更多请访问https://m.tulaoshi.com/bianchengyuyan/）（本文来源于图老师网站，更多请访问https://m.tulaoshi.com/bianchengyuyan/）//第6步：切换到结点3的父结点1Node := Node.GetParent;
（本文来源于图老师网站，更多请访问https://m.tulaoshi.com/bianchengyuyan/）（本文来源于图老师网站，更多请访问https://m.tulaoshi.com/bianchengyuyan/）//第7步：增加结点1下子结点4，作为最后一个子结点Node := YuTree.AddChild (Node);Node.Data := Pointer(4); //第8步：增加结点4的兄弟结点5，作为第一个兄弟结点Node := YuTree.AddFirst(Node);Node.Data := Pointer(5); //t第9步：切换到结点5的下一个兄弟结点3Node := Node.GetNextBrother; //第10步：在结点3下插入一个兄弟结点6Node := YuTree.Add(Node);Node.Data := Pointer(6 );
（本文来源于图老师网站，更多请访问https://m.tulaoshi.com/bianchengyuyan/）（本文来源于图老师网站，更多请访问https://m.tulaoshi.com/bianchengyuyan/）//第11步：删除结点6Node.Delete; //或YuTree.Delete(Node); //其它用法 //结点2.GetNextBrother() = 结点4 返回该结点的下一个兄弟 //结点2.GetPrevBrother() = 结点3 返回该结点的上一个兄弟 //结点1.GetFirstChild() = 结点5; 返回该结点的第一个子结点 //结点1.GetLastChild() = 结点4 返回该结点的最后一个子结点 //结点1.GetNext = 结点5 //结点1.GetPrev = 结点0 //结点2.GetFirstBrother() = 结点5 返回该结点的第一个兄弟//结点2.GetLastBrother() = 结点4 返回该结点最后一个兄弟 //YuTree.FirstNode = 结点0//YuTree.Clear(); 清空所有结点End; 说明：该在程序中是以二叉树来表示的，FDownLeft，FDownRight分别表示二叉树的左指针、右指针。原代码如下：//――――――开始―――――――――――――――――――――――――――－unit uYuTree; interface type TYuNodeAttachMode = (ynaAdd, ynaAddFirst, ynaAddChild, ynaAddChildFirst, ynaInsert); TYuTree = class; TYuNode = class(TObject) private //Self.Tree中除Root外, FUpLeft, FUpRight有且只有一个为空 FUpLeft: TYuNode; //Self.FUpLeft.FDownLeft = Self （该指针指向的结点是该结点的父结点） FUpRight: TYuNode; //Self.FUpRight.FDownRight = Self （该指针指向的结点是该结点的上一个兄弟） FDownLeft: TYuNode; //二叉树的左指针，表树的子结点 FDownRight: TYuNode; //二叉树的右指针，表示树的下一个兄弟 FOwner: TYuTree; //结点的状态信息 FDeleting: Boolean; FIsRootOfDeleted: Boolean; function GetLevel(): Integer; function GetParent(): TYuNode; procedure CutFromTree(); protected constructor Create(AOwner: TYuTree); public //Property Data: Pointer read FData write FData; Data: Pointer; //以下四个函数是基础函数,不调用其它函数，独立完成指定功能 function GetNextBrother(): TYuNode; function GetPrevBrother(): TYuNode; function GetFirstChild(): TYuNode; function GetLastChild(): TYuNode; function GetNext: TYuNode; function GetPrev: TYuNode; function GetFirstBrother(): TYuNode; function GetLastBrother(): TYuNode; procedure MoveTo(Destination: TYuNode; Mode: TYuNodeAttachMode); procedure Delete(); property Level: Integer read GetLevel; property Parent: TYuNode read GetParent; destructor Destroy();override; end; TYuTree = class(TObject) private FFirstNode: TYuNode; public function Add(Brother: TYuNode):TYuNode; function AddFirst(Brother: TYuNode):TYuNode; function AddChild(Parent: TYuNode):TYuNode; function AddChildFirst(Parent: TYuNode):TYuNode; function Insert(Brother: TYuNode):TYuNode; procedure Clear(); procedure Delete(Node: TYuNode); property FirstNode: TYuNode read FFirstNode; constructor Create(); destructor Destroy();override; end; implementation uses SysUtils, Math; { TYuNode } constructor TYuNode.Create(AOwner: TYuTree);begin if not Assigned(AOwner) then raise Exception.Create('AOwner is nil In TYuNode.Create'); FOwner := AOwner; FUpLeft := nil; FUpRight := nil; FDownLeft := nil; FDownRight := nil; FDeleting := False; FIsRootOfDeleted := False;end; destructor TYuNode.Destroy;var SubNode, WillDeleteNode: TYuNode;begin FDeleting := True; if FIsRootOfDeleted then //维护指针 CutFromTree; SubNode := GetFirstChild; while SubNode nil do begin WillDeleteNode := SubNode; SubNode := SubNode.GetNextBrother; WillDeleteNode.Free; end; inherited;end; function TYuNode.GetFirstChild: TYuNode;begin Result := FDownLeft;end; function TYuNode.GetFirstBrother: TYuNode;begin Result := Self; while Result.GetPrevBrother nil do Result := Result.GetPrevBrother;end; function TYuNode.GetLastBrother: TYuNode;begin Result := Self; while Result.GetNextBrother nil do Result := Result.GetNextBrother;end; function TYuNode.GetLastChild: TYuNode;begin Result := FDownLeft; if Result = nil then Exit; while Result.FDownRight nil do Result := Result.FDownRight;end; function TYuNode.GetLevel: Integer;var Node: TYuNode;begin Node := Self; Result := -1; repeat Node := Node.Parent; Inc(Result); until Node = nil;end; function TYuNode.GetNext: TYuNode;var Node: TYuNode;begin //1.查看第一个子结点 Result := GetFirstChild; //2.如果第1步不成功，查看下一个兄弟 if Result = nil then Result := GetNextBrother; //3.如果第2步不成功，查看父结点的下一个兄弟 //退出条件，成功找到(Result nil) 或 直到根结点仍没有找到(Node = nil) Node := Self.Parent; while (Result = nil) and (Node nil) do begin Result := Node.GetNextBrother; Node := Node.Parent; end;end; function TYuNode.GetNextBrother: TYuNode;begin Result := FDownRight;end; function TYuNode.GetParent: TYuNode;begin Result := GetFirstBrother.FUpLeft;end; function TYuNode.GetPrev: TYuNode;var Node: TYuNode;begin //1.得到上一个兄弟 Node := GetPrevBrother; //如果没有上一个兄弟，返回父结点 if Node = nil then begin Result := Self.Parent; Exit; end; //否则，返回PrevBrother.GetLastChild.GetLastChild......... Result := Node; while Node nil do begin Result := Node; Node := Node.GetLastChild; end;end; function TYuNode.GetPrevBrother: TYuNode;begin Result := FUpRight;end; procedure TYuNode.MoveTo(Destination: TYuNode; Mode: TYuNodeAttachMode);var DestParent, AddNode: TYuNode;begin if Destination = nil then begin Delete; Exit; end; if Destination.FOwner FOwner then raise Exception.CreateFmt('YuNode[@%d] Move To Another Tree In TYuNode.MoveTo', [Integer(@Self)]); DestParent := Destination.Parent; while DestParent nil do begin if DestParent = Self then raise Exception.CreateFmt('Destination Is YuNode[@%d]''s SubNode In TYuNode.MoveTo', [Integer(@Self)]); DestParent := DestParent.Parent; end; CutFromTree; case Mode of ynaAdd: AddNode := FOwner.Add(Destination); ynaAddFirst: AddNode := FOwner.AddFirst(Destination); ynaAddChild: AddNode := FOwner.AddChild(Destination); ynaAddChildFirst: AddNode := FOwner.AddChildFirst(Destination); ynaInsert: AddNode := FOwner.Insert(Destination); end; FUpLeft := AddNode.FUpLeft; FUpRight := AddNode.FUpRight; FDownRight := AddNode.FDownRight; if FUpLeft nil then FUpLeft.FDownLeft := Self; if FUpRight nil then FUpRight.FDownRight := Self; if FDownRight nil then FDownRight.FUpRight := Self; AddNode.Free;end; procedure TYuNode.Delete;begin if not FDeleting then begin FIsRootOfDeleted := True; Free; end;end; procedure TYuNode.CutFromTree;begin if Self = FOwner.FFirstNode then begin FOwner.FFirstNode := GetNextBrother; if FOwner.FFirstNode nil then FOwner.FFirstNode.FUpRight := nil; Exit; end; if FDownRight nil then //有下一个兄弟 if FUpRight nil then //有上一个兄弟 begin FUpRight.FDownRight := FDownRight; FDownRight.FUpRight := FUpRight; end else //直接指向父结点 begin FUpLeft.FDownLeft := FDownRight; FDownRight.FUpRight := nil; FDownRight.FUpLeft := FUpLeft; end else if FUpRight nil then //有上一个兄弟 FUpRight.FDownRight := nil else //直接指向父结点 FUpLeft.FDownLeft := nil;end; { TYuTree } function TYuTree.Add(Brother: TYuNode): TYuNode;var Node: TYuNode;begin if Brother = nil then if FFirstNode = nil then begin Result := TYuNode.Create(Self); FFirstNode := Result; Exit; end else Brother := FFirstNode; Node := Brother.GetLastBrother; Result := TYuNode.Create(Self); Node.FDownRight := Result; Result.FUpRight := Node;end; function TYuTree.AddChild(Parent: TYuNode): TYuNode;var Node: TYuNode;begin if Parent = nil then begin Result := Add(nil); Exit; end; Node := Parent.GetLastChild; Result := TYuNode.Create(Self); if Node = nil then begin Parent.FDownLeft := Result; Result.FUpLeft := Parent; end else begin Node.FDownRight := Result; Result.FUpRight := Node; end;end; function TYuTree.AddChildFirst(Parent: TYuNode): TYuNode;var Node: TYuNode;begin if Parent = nil then begin Result := Add(nil); Exit; end; Node := Parent.GetFirstChild; Result := TYuNode.Create(Self); if Node nil then begin Node.FUpLeft := nil; Node.FUpRight := Result; end; Result.FUpLeft := Parent; Result.FDownRight := Node; Parent.FDownLeft := Result;end; function TYuTree.AddFirst(Brother: TYuNode): TYuNode;var Node, Parent: TYuNode;begin if Brother = nil then begin Result := Add(nil); Exit; end; Node := Brother.GetFirstBrother; Parent := Node.Parent; Result := TYuNode.Create(Self); Node.FUpLeft := nil; Node.FUpRight := Result; Result.FUpLeft := Parent; Result.FDownRight := Node; if Parent nil then Parent.FDownLeft := Result else FFirstNode := Result;end; procedure TYuTree.Clear;begin while FFirstNode nil do FFirstNode.Delete; end; constructor TYuTree.Create;begin FFirstNode := nil;end; procedure TYuTree.Delete(Node: TYuNode);begin Node.Delete;end; destructor TYuTree.Destroy;begin Clear; inherited;end; function TYuTree.Insert(Brother: TYuNode): TYuNode;var Prev, Next: TYuNode;begin if Brother = nil then begin Result := Add(nil); Exit; end; if Brother.GetNextBrother = nil then Result := Add(Brother) else begin Prev := Brother; Next := Brother.GetNextBrother; Result := TYuNode.Create(Self); Prev.FDownRight := Result; Next.FUpRight := Result; Result.FUpRight := Prev; Result.FDownRight := Next; end;end; end. //――――――结束―――――――――――――――――――――――――――－ 
