void preOrder2(BinTree *root) //非遞歸前序遍歷
{
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) //非遞歸中序遍歷
{
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;
}
}
}
#include <iostream>
#include<string.h>
#include<stack>
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) //創(chuàng)建二叉樹，s為形如A(B,C(D,E))形式的字符串
{
int i;
bool isRight=false;
stack<BinTree*> s1; //存放結(jié)點(diǎn)
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) //顯示樹形結(jié)構(gòu)
{
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) //遞歸前序遍歷
{
if(root!=NULL)
{
cout<<root->data<<" ";
preOrder1(root->lchild);
preOrder1(root->rchild);
}
}
void inOrder1(BinTree *root) //遞歸中序遍歷
{
if(root!=NULL)
{
inOrder1(root->lchild);
cout<<root->data<<" ";
inOrder1(root->rchild);
}
}
void postOrder1(BinTree *root) //遞歸后序遍歷
{
if(root!=NULL)
{
postOrder1(root->lchild);
postOrder1(root->rchild);
cout<<root->data<<" ";
}
}
void preOrder2(BinTree *root) //非遞歸前序遍歷
{
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) //非遞歸中序遍歷
{
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) //非遞歸后序遍歷
{
stack<BTNode*> s;
BinTree *p=root;
BTNode *temp;
while(p!=NULL||!s.empty())
{
while(p!=NULL) //沿左子樹一直往下搜索，直至出現(xiàn)沒有左子樹的結(jié)點(diǎn)
{
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) //表示是第一次出現(xiàn)在棧頂
{
temp->isFirst=false;
s.push(temp);
p=temp->btnode->rchild;
}
else //第二次出現(xiàn)在棧頂
{
cout<<temp->btnode->data<<" ";
p=NULL;
}
}
}
}
void postOrder3(BinTree *root) //非遞歸后序遍歷
{
stack<BinTree*> s;
BinTree *cur; //當(dāng)前結(jié)點(diǎn)
BinTree *pre=NULL; //前一次訪問的結(jié)點(diǎn)
s.push(root);
while(!s.empty())
{
cur=s.top();
if((cur->lchild==NULL&&cur->rchild==NULL)||
(pre!=NULL&&(pre==cur->lchild||pre==cur->rchild)))
{
cout<<cur->data<<" "; //如果當(dāng)前結(jié)點(diǎn)沒有孩子結(jié)點(diǎn)或者孩子節(jié)點(diǎn)都已被訪問過
s.pop();
pre=cur;
}
else
{
if(cur->rchild!=NULL)
s.push(cur->rchild);
if(cur->lchild!=NULL)
s.push(cur->lchild);
}
}
}
int main(int argc, char *argv[])
{
char s[100];
while(scanf("%s",s)==1)
{
BinTree *root=(BinTree *)malloc(sizeof(BinTree));
creatBinTree(s,root);
display(root);
cout<<endl;
preOrder2(root);
cout<<endl;
inOrder2(root);
cout<<endl;
postOrder2(root);
cout<<endl;
postOrder3(root);
cout<<endl;
}
return 0;
}
