二叉树非递归遍历思路

1.将树的结点与一个FALSE标志位合一起压栈
2.判断栈中元素个数是否为空
3.栈顶元素出栈，将其标志位变成TRUE，同时将其左右树结点与FALSE标志位合一起压栈。

#define _CRT_SECURE_NO_WARNINGS
#include
#include
#include
#include "LinkStack.h"
#define MY_FALSE 0
#define MY_TRUE 1
//二叉树的结点
typedef struct BINARYNODE{
	char ch;
	struct BINARYNODE *lchild;
	struct BINARYNODE *rchild;


}BinaryNode;
//二叉树结点的非递归遍历
typedef struct BITREESTACKNODE{
	LinkNode node;
	BinaryNode *root;
	int flag;
}BitreeStackNode;
//非递归遍历
//创建栈中结点
BitreeStackNode* CreatBitreeStackNode(BinaryNode*node, int flag){
	BitreeStackNode*newnode = (BitreeStackNode*)malloc(sizeof(BitreeStackNode));
	newnode->flag = flag;
	newnode->root = node;
	return newnode;
}
void NonRecurision(BinaryNode*root){
	LinkStack *stack = Init_LinkStack();
	//把根结点扔到栈里
	Push_LinkStack(stack, (LinkNode*)CreatBitreeStackNode(root, MY_FALSE));
	while (Size_LinkStack(stack)>0)
	{
		BitreeStackNode*node = (BitreeStackNode*)Top_LinkStack(stack);
		Pop_LinkStack(stack);
		//判断弹出的结点是否为空
		if (node->root==NULL)
		{
			continue;
		}
		if (node->flag==MY_TRUE)
		{
			printf("%c", node->root->ch);
		}
		else
		{
			//当前右结点入栈
			Push_LinkStack(stack, (LinkNode*)CreatBitreeStackNode(node->root->rchild, MY_FALSE));
			//当前左结点入栈
			Push_LinkStack(stack, (LinkNode*)CreatBitreeStackNode(node->root->lchild, MY_FALSE));
			node->flag = MY_TRUE;
			//当前结点入栈
			Push_LinkStack(stack, (LinkNode*)node);
		}
	
			
		

	}

}
void CreateBinaryTree(){
	//生成结点
	BinaryNode node1 = { 'A', NULL, NULL };
	BinaryNode node2 = { 'B', NULL, NULL };
	BinaryNode node3 = { 'C', NULL, NULL };
	BinaryNode node4 = { 'D', NULL, NULL };
	BinaryNode node5 = { 'E', NULL, NULL };
	BinaryNode node6 = { 'F', NULL, NULL };
	BinaryNode node7 = { 'G', NULL, NULL };
	BinaryNode node8 = { 'H', NULL, NULL };
	//建立结点关系
	node1.lchild = &node2;
	node1.rchild = &node6;
	node2.rchild = &node3;
	node3.lchild = &node4;
	node3.rchild = &node5;
	node6.rchild = &node7;
	node7.lchild = &node8;
	//二叉树非递归打印
	NonRecurision(&node1);
}

int main(void){
	CreateBinaryTree();
	printf("\n");
	system("pause");
	return 0;
}

确定一颗树：
中序和后序可以确定一个数
中序和前序可以确定一个数
前序和后序不可以确定