头文件：

#include 
     
      struct BinaryTreeNode {    int                    m_nValue;     BinaryTreeNode*        m_pLeft;      BinaryTreeNode*        m_pRight; };
     

先序输入建立：

void Create_BT(BinaryTreeNode *&bt)//先序输入二叉树{	int d;	scanf("%d",&d);	if(d==-1)bt=NULL;	else 	{		bt=(BinaryTreeNode*)malloc(sizeof(BinaryTreeNode));		bt->m_nValue=d;		Create_BT(bt->m_pLeft);		Create_BT(bt->m_pRight);	}	}

三种遍历方法：

void PreOrder(BinaryTreeNode *bt){	if(bt!=NULL)	{		printf("%d\n",bt->m_nValue);		PreOrder(bt->m_pLeft);		PreOrder(bt->m_pRight);	}}void InOrder(BinaryTreeNode *bt){	if(bt!=NULL)	{		InOrder(bt->m_pLeft);		printf("%d\n",bt->m_nValue);		InOrder(bt->m_pRight);	}}void PostOrder(BinaryTreeNode *bt){	if(bt!=NULL)	{		PostOrder(bt->m_pLeft);		PostOrder(bt->m_pRight);		printf("%d\n",bt->m_nValue);	}}void PreOrderStack(BinaryTreeNode *bt){	BinaryTreeNode *s[20];//栈	BinaryTreeNode *p=bt;	int top=-1;	while(p||top>-1)	{		while(p)		{			printf("%d\n",p->m_nValue);			s[++top]=p;			p=p->m_pLeft;		}		if(top>-1)		{			p=s[top];			top--;			p=p->m_pRight;		}	}}void InOrderStack(BinaryTreeNode *bt){	BinaryTreeNode *s[20];//栈	BinaryTreeNode *p=bt;	int top=-1;	while(p||top>-1)	{		while(p)		{			s[++top]=p;			p=p->m_pLeft;		}		if(top>-1)		{			p=s[top];			printf("%d\n",p->m_nValue);						top--;			p=p->m_pRight;		}	}}//后序二叉树非递归struct stacknode{	BinaryTreeNode *node;	int tag;//tag=0表示左子女已访问，tag=1表示右子女已访问};void PostOrderStack(BinaryTreeNode *bt){	stacknode s[20];//栈	stacknode temp;//暂存结点信息	BinaryTreeNode *p=bt;	int top=-1;	while(p||top>-1)	{		while(p)		{			temp.node=p;			temp.tag=0;			s[++top]=temp;			p=p->m_pLeft;		}		while(top>-1&&s[top].tag==1)//右子树已访问		{			printf("%d\n",s[top--].node->m_nValue);		}		if(top>-1)		{			s[top].tag=1;			p=s[top].node;			p=p->m_pRight;		}	}}

main函数：

int main(){	while(true)	{       BinaryTreeNode *bt;	   Create_BT(bt);	   PreOrderStack(bt);	   InOrderStack(bt);	   PostOrderStack(bt);	   //PreOrder(bt);	   //InOrder(bt);	   //PostOrder(bt);	}	return 0;}