如果标题错了，让我先说对不起。
我正在学习二叉树遍历我已经获得了一些代码，我真的很难理解使用 if/else 语句和布尔逻辑的逻辑。
我必须使用 postorder、preorder 和 inorder 方法遍历树。
preorderTraversal 方法已经准备就绪并且可以工作了。
任何建议，将不胜感激。
编码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace BinaryTree
{
class BinaryTree<T>
{
class BinaryTreeNode
{
public BinaryTreeNode Left;
public BinaryTreeNode Right;
public BinaryTreeNode Parent;
public T Data;
public Boolean processed;
public BinaryTreeNode()
{
Left = null;
Right = null;
Parent = null;
processed = false;
}
}
BinaryTreeNode Root;
Comparison<T> CompareFunction;
public BinaryTree(Comparison<T> theCompareFunction)
{
Root = null;
CompareFunction = theCompareFunction;
}
public static int CompareFunction_Int(int left, int right)
{
return left - right;
}
public void preorderTraversal()
{
if (Root != null)
{
BinaryTreeNode currentNode = Root;
Boolean process = true;
int nodesProcessed = 0;
while (nodesProcessed != 11)
{
if (process)
{
Console.Write(currentNode.Data.ToString());
currentNode.processed = true;
nodesProcessed = nodesProcessed +1;
}
process = true;
if (currentNode.Left != null && currentNode.Left.processed == false)
{
currentNode = currentNode.Left;
}
else if (currentNode.Right != null && currentNode.Right.processed ==
false)
{
currentNode = currentNode.Right;
}
else if (currentNode.Parent != null)
{
currentNode = currentNode.Parent;
process = false;
}
}
}
else
{
Console.WriteLine("There is no tree to process");
}
}
public void postorderTraversal()
{
if (Root != null)
{
}
else
{
Console.WriteLine("There is no tree to process");
}
}
public void inorderTraversal()
{
if (Root != null)
{
}
else
{
Console.WriteLine("There is no tree to process");
}
}
public static int CompareFunction_String(string left, string right)
{
return left.CompareTo(right);
}
public void Add(T Value)
{
BinaryTreeNode child = new BinaryTreeNode();
child.Data = Value;
if (Root == null)
{
Root = child;
}
else
{
BinaryTreeNode Iterator = Root;
while (true)
{
int Compare = CompareFunction(Value, Iterator.Data);
if (Compare <= 0)
if (Iterator.Left != null)
{
Iterator = Iterator.Left;
continue;
}
else
{
Iterator.Left = child;
child.Parent = Iterator;
break;
}
if (Compare > 0)
if (Iterator.Right != null)
{
Iterator = Iterator.Right;
continue;
}
else
{
Iterator.Right = child;
child.Parent = Iterator;
break;
}
}
}
}
public bool Find(T Value)
{
BinaryTreeNode Iterator = Root;
while (Iterator != null)
{
int Compare = CompareFunction(Value, Iterator.Data);
if (Compare == 0) return true;
if (Compare < 0)
{
Iterator = Iterator.Left;
continue;
}
Iterator = Iterator.Right;
}
return false;
}
BinaryTreeNode FindMostLeft(BinaryTreeNode start)
{
BinaryTreeNode node = start;
while (true)
{
if (node.Left != null)
{
node = node.Left;
continue;
}
break;
}
return node;
}
public IEnumerator<T> GetEnumerator()
{
return new BinaryTreeEnumerator(this);
}
class BinaryTreeEnumerator : IEnumerator<T>
{
BinaryTreeNode current;
BinaryTree<T> theTree;
public BinaryTreeEnumerator(BinaryTree<T> tree)
{
theTree = tree;
current = null;
}
public bool MoveNext()
{
if (current == null)
current = theTree.FindMostLeft(theTree.Root);
else
{
if (current.Right != null)
current = theTree.FindMostLeft(current.Right);
else
{
T CurrentValue = current.Data;
while (current != null)
{
current = current.Parent;
if (current != null)
{
int Compare = theTree.CompareFunction(current.Data,
CurrentValue);
if (Compare < 0) continue;
}
break;
}
}
}
return (current != null);
}
public T Current
{
get
{
if (current == null)
throw new InvalidOperationException();
return current.Data;
}
}
object System.Collections.IEnumerator.Current
{
get
{
if (current == null)
throw new InvalidOperationException();
return current.Data;
}
}
public void Dispose() { }
public void Reset() { current = null; }
}
}
class TreeTest
{
static BinaryTree<int> Test = new BinaryTree<int>
(BinaryTree<int>.CompareFunction_Int);
static void Main(string[] args)
{
// Build the tree
Test.Add(5);
Test.Add(2);
Test.Add(1);
Test.Add(3);
Test.Add(3); // Duplicates are OK
Test.Add(4);
Test.Add(6);
Test.Add(10);
Test.Add(7);
Test.Add(8);
Test.Add(9);
// Test if we can find values in the tree
for (int Lp = 1; Lp <= 10; Lp++)
Console.WriteLine("Find ({0}) = {1}", Lp, Test.Find(Lp));
// Test if we can find a non-existing value
Console.WriteLine("Find (999) = {0}", Test.Find(999));
// Iterate over all members in the tree -- values are returned in sorted order
foreach (int value in Test)
{
Console.WriteLine("Value: {0}", value);
}
Console.WriteLine("Preorder traversal");
Test.preorderTraversal();
Console.ReadKey();
}
}
}