Recursive and non-recursive forms of back/hierarchy traversal in front of a binary tree (c + +)

/* Recursive and non-recursive form *///***************void preOrder1 (binarytreenode* proot) {if (Proot==null) return for the back/hierarchy traversal in front of the two fork tree;    cout<<proot->value;    if (proot->left!=null) preOrder1 (proot->left); if (proot->right!=null) preOrder1 (proot->right);}    void PreOrder2 (binarytreenode* proot) {stack<binarytreenode*> s;     Binarytreenode *p=proot;    if (proot==null) return; while (p!=null| |!           S.empty ()) {while (p!=null) {cout<<p->value<< "";           S.push (P);       p=p->left;           } if (!s.empty ()) {p=s.top ();           S.pop ();       p=p->right;    }}}void PreOrder2 (binarytreenode* proot) {if (proot==null) return;      Stack<binarytreenode*> s;    S.push (root);    Binarytreenode* p;      while (!s.empty ()) {p = s.top ();        cout<<p->data;//Traverse root node s.pop ();  if (p>right) {s.push (p->right); Stack the right subtree first} iF (p->left) {s.push (p->left);        Then the left subtree is pressed to stack}}}//*****************//in the sequence traversal void InOrder1 (binarytreenode* proot) {if (proot==null) return;    if (proot->left!=null) inOrder1 (proot->left);    cout<<proot->value; if (proot->right!=null) inOrder1 (proot->right);}    void InOrder2 (binarytreenode* proot) {stack<binarytreenode*> s;     Binarytreenode *p=proot;    if (proot==null) return; while (p!=null| |!           S.empty ()) {while (p!=null) {s.push (P);       p=p->left;           } if (!s.empty ()) {p=s.top ();           cout<<p->value<< "";           S.pop ();       p=p->right;    }}}//*****************//post-traversal of void PostOrder1 (binarytreenode* proot) {if (proot==null) return;    PostOrder1 (Proot->left);    PostOrder1 (Proot->right); cout<<proot->value<< "";} void PostOrder2 (binarytreenode* proot) {stack<binarytrEenode*> s;    Binarytreenode *cur;        Binarytreenode *pre=null;//Records the node of the previous output s.push (proot);//root node into the stack while (!s.empty ()) {cur=s.top (); if ((cur->left==null&&cur->right==null) | | | (pre!=null&& (pre==cur->left| |  Pre==cur->right)) {//left child and right child are both empty, or the left child or right child of the current node has traversed the cout<<cur->value<< "            ";            S.pop ();        Pre=cur;            } else {if (cur->right!=null) S.push (cur->right);        if (cur->left!=null) S.push (cur->left);      }}}//*****************//hierarchy traversal, using the queue void Printfromtoptobottom (binarytreenode* proot) {if (Proot = = NULL) return;     Deque<binarytreenode *> Dequetreenode;    Dequetreenode.push_back (Proot);        while (Dequetreenode.size ()) {Binarytreenode *pnode = Dequetreenode.front ();         Dequetreenode.pop_front ();        cout<<pnode->m_nvalue<< ""; if (PNODE-&GT;m_pleft) Dequetreenode.push_back (pnode->m_pleft);    if (pnode->m_pright) dequetreenode.push_back (pnode->m_pright);      }}//Depth First Traversal ~ First order traversal void Dfs (binarytreenode* root) {stack<binarytreenode* *> nodestack;    Nodestack.push (root);    Node *node;      while (!nodestack.empty ()) {node = Nodestack.top ();        cout<<node->data;//Traverse root node Nodestack.pop ();  if (node->rchild) {Nodestack.push (node->rchild);  Press the right subtree first to stack} if (node->lchild) {Nodestack.push (node->lchild);      Re-stack the left subtree}}}//breadth-First traversal ~ hierarchy traversal void BFs (binarytreenode* root) {queue<binarytreenode* *> nodequeue;    Nodequeue.push (root);    Node *node;        while (!nodequeue.empty ()) {node = Nodequeue.front ();        Nodequeue.pop ();  cout<<node->data;//traverse the root node if (node->lchild) {Nodequeue.push (node->lchild); Queue the left subtree first} if (Node->rchild) {nodequEue.push (Node->rchild); Queue the right subtree again}}}

　　

Recursive and non-recursive forms of back/hierarchy traversal in front of a binary tree (c + +)