[Learn Little bit by bit-Data Structure-binary tree] binary tree traversal (full)

#include <stdio.h>#include <string.h>#include <stdlib.h>#include <queue>#include <stack> #include <iostream> #include <malloc.h>#define LEAF -1using namespace std;typedef struct BTreeNode{     BTreeNode* lchild;     BTreeNode* rchild;     int value;               }BTreeNode,*Btree;BTreeNode* createTree(){     BTreeNode* T;     int t;           scanf("%d",&t);     if(t == LEAF){          T = NULL;     }else{          T = (BTreeNode *) malloc(sizeof(BTreeNode));          T->value = t;          T->lchild = createTree();          T->rchild = createTree();         }     return T;}void visit(BTreeNode * root){     printf("%d ",root->value); } void preOrder(BTreeNode* root){     if(root != NULL){         visit(root);     }     if(root->lchild != NULL){         preOrder(root->lchild);                 }     if(root->rchild !=NULL){         preOrder(root->rchild);     }}void inOrder(BTreeNode* root){     if(root->lchild != NULL){         inOrder(root->lchild);                 }     if(root != NULL){         visit(root);     }     if(root->rchild !=NULL){         inOrder(root->rchild);     }}void postOrder(BTreeNode* root){     if(root->lchild != NULL){         postOrder(root->lchild);                 }     if(root->rchild !=NULL){         postOrder(root->rchild);     }     if(root != NULL){         visit(root);      }}void BFSVisit(BTreeNode* root){    if(root == NULL){         return ;             }      queue<BTreeNode*> que;     que.push(root);     while(!que.empty()){          BTreeNode *tmp = que.front();          que.pop();           visit(tmp);           if(tmp->lchild != NULL){              que.push(tmp->lchild);                         }          if(tmp->rchild != NULL){              que.push(tmp->rchild);           }                         } } void non_recur_preOrder(BTreeNode * root){     stack<BTreeNode *> s;     BTreeNode * tmp = root;      while(tmp != NULL|| !(s.empty())){         while(tmp != NULL){             visit(tmp);             s.push(tmp);             tmp = tmp->lchild;                   }                  while(!(s.empty())){             tmp = s.top();             s.pop();             tmp = tmp->rchild;             }               } } void non_recur_inOrder(BTreeNode * root){     stack<BTreeNode *> s;     BTreeNode * tmp = root;      while(tmp != NULL|| !(s.empty())){         while(tmp != NULL){             s.push(tmp);             tmp = tmp->lchild;                   }                  while(!(s.empty())){             tmp = s.top();             visit(tmp);              s.pop();             tmp = tmp->rchild;             }               } } void non_recur_postOrder(BTreeNode *root){     stack<int> tag;     stack<BTreeNode *> s;     BTreeNode* tmp = root;     do{         while(tmp != NULL){             s.push(tmp);             tag.push(0);             tmp = tmp->lchild;                }         while(!s.empty() && tag.top()==1){             tmp = s.top();             s.pop();             tag.pop();             visit(tmp);             }         if(!s.empty()){             tag.pop();             tag.push(1);             tmp = (s.top())->rchild;          }        }while(!(s.empty()));} main(){    BTreeNode * root;    root = createTree();    printf("preOrder :");    preOrder(root);    printf("\n");    printf("preOrder :");    non_recur_preOrder(root);    printf("\n");    printf("inOrder :");    inOrder(root);    printf("\n");    printf("inOrder :");    non_recur_inOrder(root);    printf("\n");    printf("postOrder :");    postOrder(root);    printf("\n");    printf("postOrder :");    non_recur_postOrder(root);    printf("\n");    system("pause");    return 0;       }