二叉树的遍历

#include <iostream>#include <windows.h>#include <stack>#include <set>using namespace std;struct TreeNode {int value;TreeNode* lChild;TreeNode* rChild;TreeNode(int v) :value(v), lChild(NULL), rChild(NULL){}};void PrintValue(int value){cout << value << " ";}void InOrder(TreeNode* root){cout << "*****************中序遍历*********************" << endl;if (NULL == root)return;stack<TreeNode*> treeStack;treeStack.push(root);TreeNode*  curLeftChild = root->lChild;while (curLeftChild){treeStack.push(curLeftChild);curLeftChild = curLeftChild->lChild;}while (!treeStack.empty()){TreeNode* curNode = treeStack.top();treeStack.pop();PrintValue(curNode->value);if (curNode->rChild){treeStack.push(curNode->rChild);curNode = curNode->rChild;while (curNode->lChild){treeStack.push(curNode->lChild);curNode = curNode->lChild;}}}cout << endl;cout << "**********************************************" << endl;}void InOrderR(TreeNode* root){if (NULL == root)return;InOrderR(root->lChild);PrintValue(root->value);InOrderR(root->rChild);}void PreOrder(TreeNode* root){cout << "*****************前序遍历*********************" << endl;if (NULL == root)return;TreeNode* curNode = root;stack<TreeNode*> treeS;while (curNode){PrintValue(curNode->value);treeS.push(curNode);curNode = curNode->lChild;}while (!treeS.empty()){curNode = treeS.top();treeS.pop();if (curNode->rChild){curNode = curNode->rChild;PrintValue(curNode->value);treeS.push(curNode);while (curNode->lChild){curNode = curNode->lChild;PrintValue(curNode->value);treeS.push(curNode);}}}cout << endl;cout << "**********************************************" << endl;}void PreOrderR(TreeNode* root){if (NULL == root)return;PrintValue(root->value);PreOrderR(root->lChild);PreOrderR(root->rChild);}void PostOrder(TreeNode* root){cout << "*****************后序遍历*********************" << endl;if (NULL == root)return;stack<TreeNode*> treeStack;set<TreeNode*> reachSet;treeStack.push(root);TreeNode*  curLeftChild = root->lChild;while (curLeftChild){treeStack.push(curLeftChild);curLeftChild = curLeftChild->lChild;}while (!treeStack.empty()){TreeNode* curNode = treeStack.top();if (curNode->rChild&&(reachSet.find(curNode)== reachSet.end())){reachSet.insert(curNode);curNode = curNode->rChild;treeStack.push(curNode);while (curNode->lChild){treeStack.push(curNode->lChild);curNode = curNode->lChild;}}else{PrintValue(curNode->value);treeStack.pop();}}cout << endl;cout << "**********************************************" << endl;}void PostOrderR(TreeNode* root){if (NULL == root)return;PostOrderR(root->lChild);PostOrderR(root->rChild);PrintValue(root->value);}int main(int argc, char* argv[]){TreeNode* root = new TreeNode(1);TreeNode* l1 = new TreeNode(2);TreeNode* r1 = new TreeNode(3);root->lChild = l1;l1->rChild = r1;TreeNode* l2 = new TreeNode(4);TreeNode* r2 = new TreeNode(5);r1->lChild = l2;l2->rChild = r2;TreeNode* l3 = new TreeNode(6);TreeNode* r3 = new TreeNode(7);r2->lChild = l3;l3->rChild = r3;InOrder(root);cout << "*****************中序遍历递归*********************" << endl;InOrderR(root);cout << endl;cout << "**********************************************" << endl;PreOrder(root);cout << "*****************前序遍历递归*********************" << endl;PreOrderR(root);cout << endl;cout << "**********************************************" << endl;PostOrder(root);cout << "*****************后序遍历递归*********************" << endl;PostOrderR(root);cout << endl;cout << "**********************************************" << endl;system("pause");return 0;}