二叉搜索树的实现

// bogo.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <stdio.h>
#include <iostream>
#include <time.h>
using namespace std;

struct Tree
{
	int key;
	Tree *left;
	Tree *right;
	Tree *p;
};

Tree *gRoot = NULL;

//插入节点
void fnInsert(Tree *date)
{
	if (!gRoot)
	{
		gRoot = new Tree;
		gRoot->key = date->key;
		gRoot->left = NULL;
		gRoot->right = NULL;
		gRoot->p = NULL;
	}
	else
	{
		Tree *x = gRoot;
		Tree *y = NULL;
		while (x != NULL)
		{
			y = x;
			if (date->key < x->key)
				x = x->left;
			else x = x->right;
		}

		date->p = y;

		if(date->key < y->key)
			y->left = date;
		else y->right = date;

		date->left = NULL;
		date->right = NULL;

	}
}

void fnSwapNode(Tree *src,Tree *des)
{
	if (src->p == NULL)
		gRoot = des;
	else if (src == src->p->left)
		src->p->left = des;
	else src->p->right = des;

	if(des != NULL)
		des->p = src->p;

}

//中序遍历树
void fnShowTree(Tree *date)
{
	if (!date) return ;
	fnShowTree(date->left);
	cout<<date->key<<" ";
	fnShowTree(date->right);
}

Tree *fnFindMin(Tree *src)
{
	while (src->left != NULL)
		src = src->left;
	return src;
}

void fnDeleteNode(Tree *des)//删除节点
//删除节点分四种情况
{
	if (des->left == NULL)
		fnSwapNode(des,des->right);
	else if(des->right == NULL)
		fnSwapNode(des,des->left);
	else
	{
		Tree *x = fnFindMin(des->right);
		if (x->p != des)
		{
			fnSwapNode(x,x->right);
			x->right = des->right;
			x->right->p = x;
		}
		fnSwapNode(des,x);
		x->left = des->left;
		x->left->p = x;
	}
	delete(des);
}

Tree *fnSearchTree(int key)//寻找树
{
	if (gRoot->key == key)
		return gRoot;
	else
	{
		Tree *temp = gRoot;
		while (gRoot != NULL)
		{
			if (key < temp->key)
				temp = temp->left;
			else if (key > temp->key)
				temp = temp->right;
			else return temp;
		}
		return NULL;
	}
}

void fnDestoryTree(Tree *x)//销毁树
{
	if ( x == NULL) return;
	else
	{
		fnDestoryTree(x->left);
		fnDestoryTree(x->right);
		delete(x);
	}
}

void fnRandBuildTree(int num)//随机生出num个节点并插入二叉树
{
	srand((int)time(0));
	Tree *temp = NULL;
	while (num--)
	{
		temp = new Tree;
		temp->key = rand()%100;
		fnInsert(temp);
	}
}

int _tmain(int argc, _TCHAR* argv[])
{
	int x;
	Tree *temp;
	while (true)
	{
		cout<<"1.随机生成二叉树"<<endl;
		cout<<"2.插入节点"<<endl;
		cout<<"3.删除节点"<<endl;
		cout<<"4.浏览节点"<<endl;
		cout<<"5.退出程序"<<endl;

		cin>>x;
		switch (x)
		{
		case 1:
			{
			cout<<"输入节点数:";
			cin>>x;
			fnRandBuildTree(x);
			break;
			}
		case 2:
			{
				cout<<"输入节点数:";
				temp = new Tree;
				cin>>temp->key;
				fnInsert(temp);
				break;
			}
		case 3:
			{
				cout<<"输入要删除节点数据:";
				cin>>x;
				fnDeleteNode(fnSearchTree(x));
				break;
			}
		case 4:
			{
				cout<<"遍历输出"<<endl;
				fnShowTree(gRoot);
				break;
			}
		case 5:
			{
				fnDestoryTree(gRoot);
				exit(-1);
			}
		default:
			break;
		}
		system("pause");
		system("cls");
	}

	return 0;
}