二叉树的三种遍历的方法(递归和非递归完整版)

#include<iostream>
#include<stack>
using namespace std;

template<typename T>
struct TreeNode
{
	T info;
	TreeNode<T>* left;
	TreeNode<T>* right;
};

template<typename T>
void visit(T& info)
{
	cout<<info<<endl;
}


template<typename T>
void recursivePreorderTraverse(TreeNode<T>* head)
{
	if(head==NULL) return;
	visit(head->info);
	recursivePreorderTraverse(head->left);
	recursivePreorderTraverse(head->right);
}

template<typename T>
void recursiveInorderTraverse(TreeNode<T>* head)
{
	if(head==NULL) return;
	recursiveInorderTraverse(head->left);
	visit(head->info);
	recursiveInorderTraverse(head->right);
}

template<typename T>
void recursivePostorderTraverse(TreeNode<T>* head)
{
	if(head==NULL) return;
	recursivePostorderTraverse(head->left);
	recursivePostorderTraverse(head->right);
	visit(head->info);
}

template<typename T>
void nonrecusivePreorderTraverse(TreeNode<T>* head)
{
	if(head==NULL) return;

	stack<TreeNode<T>*> treeStack;
	treeStack.push(head);
	TreeNode<T>* top=NULL;
	
	while(!treeStack.empty())
	{
		treeStack.pop(top);
		visit(top->info);
		if(top->left!=NULL) treeStack.push(top->left);
		if(top->right!=NULL) treeStack.push(top->right);
	}
}

template<typename T>
void nonrecusiveInorderTraverse(TreeNode<T>* head)
{
	if(head==NULL) return;

	stack<TreeNode<T>*> treeStack;
	TreeNode<T>* index = head;
	
	while(index!=NULL||!treeStack.empty())
	{
		while(index!=NULL)
		{
			treeStack.push(index);
			index = index->left;
		}

		if(!treeStack.empty())
		{
			treeStack.pop(index);
			visit(index->info);
			index = index->right;
		}
	}
}

template<typename T>
void nonrecursivePostorderTraverse(TreeNode<T>* head)
{
	if(head==NULL) return;

	stack<TreeNode<T>*> treeStack1;
	stack<TreeNode<T>*> treeStack2;

	treeStack1.push(head);

	while(!treeStack1.empty())
	{
		TreeNode<T>* top = treeStack1.top();
		treeStack1.pop();

		treeStack2.push(top);
		if(top->right!=NULL) treeStack1.push(top->right);
		if(top->left!=NULL) treeStack1.push(top->left);
	}

	while(!treeStack2.empty())
	{
		TreeNode<T>* top = treeStack2.top();
		treeStack2.pop();

		visit(top);
	}

}

int main()
{
}