二叉树 递归 非递归

#include <iostream> #include <string.h> #include <stack> #include <windows.h> using namespace std; typedef struct node { char data; struct node *lchild,*rchild; }BinTree; typedef struct node1 { BinTree *btnode; bool isFirst; }BTNode; void creatBinTree(char *s,BinTree *&root) //创建二叉树，s为形如A(B,C(D,E))形式的字符串 { int i; bool isRight=false; stack<BinTree*> s1; //存放结点 stack<char> s2; //存放分隔符 BinTree *p,*temp; root->data=s[0]; root->lchild=NULL; root->rchild=NULL; s1.push(root); i=1; while(i<strlen(s)) { if(s[i]=='(') { s2.push(s[i]); isRight=false; } else if(s[i]==',') { isRight=true; } else if(s[i]==')') { s1.pop(); s2.pop(); } else if(isalpha(s[i])) { p=(BinTree *)malloc(sizeof(BinTree)); p->data=s[i]; p->lchild=NULL; p->rchild=NULL; temp=s1.top(); if(isRight==true) { temp->rchild=p; cout<<temp->data<<"的右孩子是"<<s[i]<<endl; } else { temp->lchild=p; cout<<temp->data<<"的左孩子是"<<s[i]<<endl; } if(s[i+1]=='(') s1.push(p); } i++; } } void display(BinTree *root) //显示树形结构 { if(root!=NULL) { cout<<root->data; if(root->lchild!=NULL) { cout<<'('; display(root->lchild); } if(root->rchild!=NULL) { cout<<','; display(root->rchild); cout<<')'; } } } void preOrder1(BinTree *root) //递归前序遍历 { if(root!=NULL) { cout<<root->data<<" "; preOrder1(root->lchild); preOrder1(root->rchild); } } void inOrder1(BinTree *root) //递归中序遍历 { if(root!=NULL) { inOrder1(root->lchild); cout<<root->data<<" "; inOrder1(root->rchild); } } void postOrder1(BinTree *root) //递归后序遍历 { if(root!=NULL) { postOrder1(root->lchild); postOrder1(root->rchild); cout<<root->data<<" "; } } void preOrder2(BinTree *root) //非递归前序遍历 { stack<BinTree*> s; BinTree *p=root; while(p!=NULL||!s.empty()) { while(p!=NULL) { cout<<p->data<<" "; s.push(p); p=p->lchild; } if(!s.empty()) { p=s.top(); s.pop(); p=p->rchild; } } } void inOrder2(BinTree *root) //非递归中序遍历 { stack<BinTree*> s; BinTree *p=root; while(p!=NULL||!s.empty()) { while(p!=NULL) { s.push(p); p=p->lchild; } if(!s.empty()) { p=s.top(); cout<<p->data<<" "; s.pop(); p=p->rchild; } } } void postOrder2(BinTree *root) //非递归后序遍历 { stack<BTNode*> s; BinTree *p=root; BTNode *temp; while(p!=NULL||!s.empty()) { while(p!=NULL) //沿左子树一直往下搜索，直至出现没有左子树的结点 { BTNode *btn=(BTNode *)malloc(sizeof(BTNode)); btn->btnode=p; btn->isFirst=true; s.push(btn); p=p->lchild; } if(!s.empty()) { temp=s.top(); s.pop(); if(temp->isFirst==true) //表示是第一次出现在栈顶 { temp->isFirst=false; s.push(temp); p=temp->btnode->rchild; } else //第二次出现在栈顶 { cout<<temp->btnode->data<<" "; p=NULL; } } } }