输入一颗二元查找树，将该树转换为它的镜像（递归解法）

代码自己敲的，中间建树的时候遇到了麻烦，以前是先申请空间给根节点，这样的话根节点就需要单独处理。

突发奇想用了下双重指针，对双重指针的作用和用法有了更好的理解。

用递归解法做这个问题不难，主要熟悉了一下建树，打印树的代码。

中间有调试代码，就不改了，方便看执行过程。

#include<stdio.h>
#include<stdlib.h>

#define DEBUG(i) printf("Here " #i " is OK\n");

typedef struct BSTreeNode
{
	int m_nValue;
	struct BSTreeNode *m_pLeft;
	struct BSTreeNode *m_pRight;
}BSTreeNode;

//====================================================================

void iniTree(struct BSTreeNode ** mytree, int data);
void printTree(struct BSTreeNode * mytree);
void translate(struct BSTreeNode * mytree);

//====================================================================

int main()
{

	struct BSTreeNode * mytree = NULL;
	int num, temp, i;
	
	printf("Please input how many numbers in your tree\n");
	scanf("%d", &num);

	for(i = 0; i < num; i++)
	{
		DEBUG(1);
		scanf("%d", &temp);
		iniTree(&mytree, temp);
	}

	translate(mytree);
	
	printTree(mytree);
	DEBUG(0);
	printf("Congratulations!\n");
	return 0;
}

void iniTree(struct BSTreeNode ** mytree, int data)
{
	DEBUG(2);
	if(*mytree == NULL)
	{
		*mytree = (struct BSTreeNode * )malloc(sizeof(BSTreeNode)); //here change the pointer to an addr, so ** is needed
		(*mytree)->m_nValue = data;
		(*mytree)->m_pLeft = NULL;
		(*mytree)->m_pRight = NULL;
		return;
	}
	else if((*mytree)->m_nValue >= data)
		iniTree(&((*mytree)->m_pLeft), data);
	else
		iniTree(&((*mytree)->m_pRight), data);
}

void printTree(struct BSTreeNode * mytree)
{
	DEBUG(3);

	if(mytree != NULL)
	{
		printf("%d\n", mytree->m_nValue);
		if(mytree->m_pLeft != NULL)
			printTree(mytree->m_pLeft);
		if(mytree->m_pRight != NULL)
			printTree(mytree->m_pRight);
	}
}

void translate(struct BSTreeNode * mytree)
{
	if(!mytree)
		return ;
	if(mytree->m_pLeft)
		translate(mytree->m_pLeft);
	if(mytree->m_pRight)
		translate(mytree->m_pRight);
	struct BSTreeNode * temp;
	temp = mytree->m_pLeft;
	mytree->m_pLeft = mytree->m_pRight;
	mytree->m_pRight = temp;
}