中序遍历二叉树（递归 & 非递归）

k_eckel：http://www.mscenter.edu.cn/blog/k_eckel & http://k-eckel.cnblogs.com

       二叉树是很有用的一种数据结构，遍历则是其基本操作，这里列出实是保证完整性。几个备用的结构定义和函数：

//二叉树节点定义

class TreeNodeElement

{

       public:

              TreeNodeElement();

 

              TreeNodeElement(int value);

             

              TreeNodeElement(int value,TreeNodeElement* l,TreeNodeElement* r);

 

              ~TreeNodeElement();

 

       private:

       public:

              int _value;

 

              TreeNodeElement* _l;

 

              TreeNodeElement* _r;

};

 

typedef TreeNodeElement* TreeNode;

//递归实现（visit）

void Visit(TreeNode node)

{

       cout<<node->_value<<" ";

}

       二叉树中序遍历的递归和非递归实现：

//递归遍历

void BinRetriveATree(TreeNode root,void (* visit)(TreeNode))

{

       if (root)

       {

              BinRetriveATree(root->_l,visit);

              (*visit)(root);

              BinRetriveATree(root->_r,visit);

       }

      

}

//非递归遍历，添加#include <stack>

void BinRetriveATreeWithoutRecurve(TreeNode root,void (* visit)(TreeNode))

{

       stack<TreeNode> tree;

 

       while ((root != NULL) || (!tree.empty()))

       {

              while (root != NULL)

              {

                     tree.push(root);

 

                     root = root->_l;

              }

 

              if (!tree.empty())

              {

                     root = tree.top();

 

                     tree.pop();

 

                     visit(root);

                    

                     root = root->_r;   //转到右子树

 

              }

       }

}