C#的确是一个很好的面向对象语言，我看《数据结构(第二版)》那本书应该出本用C#描述的版本。下面是我用C#写的一棵树。先用接口把节点做了抽象定义，这样在实现遍历，插入等操作的时候只对接口进行操作。在程序中，我尽量使用C#的特性，如接口，属性，玫举，这样代码虽然看起来比较冗长，但是，当代码越来越长的时候，你就会从中看到优点，因为合理的结构让你永远思路清晰。这课树我只能算写了一个开头，因为如果要把所有类型的树和加在他们之上的算法都写出来，我看没有1~2k 行程序是绝对不行的，不过，只要有时间，我一定会继续写的，同时希望大家也写，把这个代码库完善起来。
using System;
using System.Collections;
///
/// author 何潇(sailer)( he_x@263.net )
///
namespace Tree
{
/// <summary>
/// LEFT左子树，RIGHT右子树
/// </summary>
enum Position{LEFT,RIGHT};
/// <summary>
/// LINK指向孩子，THREAD指向后继
/// </summary>
enum Tag{LINK,THREAD};
/// <summary>
/// 二叉树节点的抽象定义
/// </summary>
interface IBinNode
{
bool isLeaf();
object Element{get;set;}
IBinNode Left{get;set;}
IBinNode Right{get;set;}
}
/// <summary>
/// 遍历，线索化等操作的接口
/// </summary>
interface ITravelBinTree
{
void PreOrderTravel();
void InOrderTravel();
void RevOrderTravel();
void Print(IBinNode t);
}
interface IInsertBinTree
{
void Insert(IBinNode node,Position pos);
}
/// <summary>
/// Normal actualize of bintree
/// </summary>
class BinNodePtr : IBinNode
{
protected object element;
protected IBinNode lchild;
protected IBinNode rchild;
public BinNodePtr(object e,IBinNode left,IBinNode right)
{
element = e;
lchild = left;
rchild = right;
}
public BinNodePtr(object e)
{
element = e;
lchild = rchild = null;
}
public BinNodePtr()
{
element = null;
lchild = rchild =null;
}
public bool isLeaf()
{
if(lchild==null && rchild==null)
return true;
return false;
}
public object Element
{
get{return element;}
set{element = value;}
}
public IBinNode Left
{
get
{
return lchild;
}
set
{
lchild = value;
}
}
public IBinNode Right
{
get
{
return rchild;
}
set
{
rchild = value;
}
}
}
class BinNodeLine : BinNodePtr,IBinNode
{
private Tag ltag,rtag;
public BinNodeLine(object e,IBinNode left,IBinNode right) :base(e,left,right)
{ltag = rtag = Tag.LINK;}
public BinNodeLine(object e) : base(e)
{ltag = rtag = Tag.LINK;}
public Tag LTag
{
get{return ltag;}
set{ltag = value;}
}
public Tag RTag
{
get{return rtag;}
set{rtag = value;}
}
}
class TravelBinTree : ITravelBinTree,IInsertBinTree
{
const int INIT_TREE_SIZE=20;
private IBinNode tree;
private BinNodeLine head; //线索化后的头指针
private IBinNode prenode; //指向最近访问过的前驱节点
public TravelBinTree()
{
tree = new BinNodePtr();
}
public TravelBinTree(IBinNode INode)
{
tree = INode;
}
/// <summary>
/// 先序遍历树,用非递归算法实现
/// </summary>
/// <remarks>非递归实现</remarks>
public void PreOrderTravel()
{
IBinNode temptree;
Stack stk = new Stack(INIT_TREE_SIZE);
if(tree == null)
throw(new InvalidOperationException("访问的树为空"));
temptree = tree;
stk.Push(tree);
while(stk.Count!=0)
{
while(temptree!=null)
{
Print(temptree);
stk.Push(temptree.Left);
temptree = temptree.Left;
}
stk.Pop(); // 空指针退栈
if(stk.Count != 0)
{
temptree=(IBinNode)stk.Pop();
stk.Push(temptree.Right);
temptree = temptree.Right;
}
}
}
public void InOrderTravel()
{
InOrderTravel(tree);
}
private void InOrderTravel(IBinNode t)
{
if(t==null) return;
InOrderTravel(t.Left);
Print(t);
InOrderTravel(t.Right);
}
public void RevOrderTravel()
{
RevOrderTravel(tree);
}
private void RevOrderTravel(IBinNode t)
{
if(t==null) return;
RevOrderTravel(t.Left);
RevOrderTravel(t.Right);
Print(t);
}
public void Print(IBinNode t)
{
Console.Write(t.Element + ",");
}
public void Insert(IBinNode node,Position pos)
{
if(node == null)
throw(new InvalidOperationException("不能将空节点插入树"));
switch(pos)
{
case Position.LEFT : tree.Left = node;break;
case Position.RIGHT: tree.Right = node;break;
}
}
/// <summary>
/// 按照先序遍历顺序遍历树
/// </summary>
public void TreeBuilder()
{
Stack stk = new Stack(INIT_TREE_SIZE);
stk.Push(tree);
Position pos;
string para;
pos = Position.LEFT;
IBinNode baby,temp;
while(true)
{
para = Console.ReadLine();
if(para == "")
{
if(pos == Position.RIGHT)
{
stk.Pop();
while(stk.Count!=0 && ((IBinNode)stk.Peek()).Right!=null)
stk.Pop();
if(stk.Count ==0) break;
}
else
pos = Position.RIGHT;
}
else
{
if(tree.GetType().Equals()==true)
baby = new BinNodePtr(para);
temp = (IBinNode)stk.Peek();
if(pos == Position.LEFT)
temp.Left = baby;
else
temp.Right = baby;
pos = Position.LEFT;
stk.Push(baby);
}
}
}
/// <summary>
/// 中序线索化
/// </summary>
public void InOrderThreading()
{
head = new BinNodeLine("");
head.RTag = Tag.THREAD;
head.Right = head;
if(tree == null) head.Left = head;
else
{
head.Left = tree; prenode = head;
}
}
/// <summary>
/// 中序线索化的递归实现
/// </summary>
/// <param name="t"></param>
private void InThreading(IBinNode t)
{
if(t==null)
return;
else
{
InThreading(t.Left);
// if(left
}
}
}
/// <summary>
/// Summary description for Class1.
/// </summary>
class Class1
{
/// <summary>
/// 测试控制台
/// </summary>
/// <param name="args"></param>
static void Main(string[] args)
{
string para = null;
para = Console.ReadLine();
BinNodePtr root = new BinNodePtr(para);
TravelBinTree t = new TravelBinTree(root);
t.TreeBuilder();
t.PreOrderTravel();
Console.WriteLine("");
t.InOrderTravel();
Console.WriteLine("");
t.RevOrderTravel();
}
}
}
非常希望和大家交流( he_x@263.net )
……