一.使用c++进行前中后遍历，层次和深度遍历（非递归）

二.代码

#include<iostream>
#include<queue>
#include<vector>
#include<stack>
using namespace std;
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
        val(x), left(NULL), right(NULL) {
    }
};
void PreOrder(TreeNode *T)//前序遍历
{
    if (!T)
        return;
    if (T)
    {
        cout << T->val<<endl;
        PreOrder(T->left);
        PreOrder(T->right);
    }
    
}
void PreOrder(TreeNode *T)//非递归，前序遍历
{
    if (T == NULL)
    {
        return;
    }
    stack<TreeNode*>s;
    s.push(T);
    TreeNode *temp;
    while (!s.empty())
    {
        temp = s.top();
        cout << temp->val;
        s.pop();
        if (temp->left)
        {
            s.push(temp->left);
        }
        if (temp->right)
        {
            s.push(temp->right);
        }
    }
}

void InOrder(TreeNode *T)//中序遍历
{
    if (!T)
        return;
    InOrder(T->left);
    cout << T->val;
    InOrder(T->right);
}

void PostOrder(TreeNode *T)//后序遍历
{
    if (!T)
        return;
    PostOrder(T->left);
    PostOrder(T->right);
    cout << T->val;
}
void Levelorder(TreeNode *T)//层析遍历
{
    if (!T)
        return;
    TreeNode *temp;
    queue<TreeNode*>q;
    q.push(T);
    while (!q.empty())
    {
        temp = q.front();
        cout << temp->val;
        if (temp->left)
            q.push(temp->left);
        if (temp->right)
            q.push(temp->right);
        q.pop();
    }
}
void DeepOrder(TreeNode *T)//深度遍历
{
    if (!T)
        return;
    TreeNode *temp;
    stack<TreeNode*>s;
    s.push(T);
    while (!s.empty())
    {
        temp = s.top();
        cout << temp->val;
        s.pop();
        if (temp->left)
            s.push(temp->left);
        if (temp->right)
            s.push(temp->right);
    }
}