5)二叉树[1]二叉树的遍历（先序、中序、后序）

 1 #include "iostream"
 2 using namespace std;
 3 
 4 typedef char type;
 5 struct bnode{
 6     type data;
 7     bnode *lchild,*rchild;
 8 };
 9 
10 class tree{
11 public:
12     tree();//初始化
13     ~tree();
14     void create_tree(bnode *&T);//建立二叉树
15     void preorder(bnode *T);//先序遍历
16     void inorder(bnode *T);//中序遍历
17     void postorder(bnode *T);//后序遍历
18 private:
19     int count;//元素个数统计
20 };
21 
22 tree::tree()//初始化
23 {
24     count = 0;
25 }
26 
27 void tree::create_tree(bnode *&T)//建立二叉树
28 {
29     type x;
30     cin>>x;
31     if(x=='.')T=NULL;
32     else {
33         T = new bnode;
34         T->data = x;
35         count++;
36         create_tree(T->lchild);
37         create_tree(T->rchild);
38     }
39 }
40 
41 void tree::preorder(bnode*T)//先序遍历
42 {
43     if(T!=NULL)
44     {
45         cout<<T->data<<" ";
46         preorder(T->lchild);
47         preorder(T->rchild);
48     }
49 }
50 
51 void tree::inorder(bnode*T)//中序遍历
52 {
53     if(T!=NULL)
54     {
55         inorder(T->lchild);
56         cout<<T->data<<" ";
57         inorder(T->rchild);
58     }
59 }
60 
61 void tree::postorder(bnode*T)//后序遍历
62 {
63     if(T!=NULL)
64     {
65         postorder(T->lchild);
66         postorder(T->rchild);
67         cout<<T->data<<" ";
68     }
69 }
70 
71 tree::~tree(){}
72 
73 int main()
74 {
75     tree Tree;
76     bnode *T;
77     cout<<"Create Tree:";
78     Tree.create_tree(T);
79     cout<<"Tree finished!"<<endl;
80     cout<<"preorder Tree:";
81     Tree.preorder(T);
82     cout<<endl;
83     cout<<"inorder Tree:";
84     Tree.inorder(T);
85     cout<<endl;
86     cout<<"postorder Tree:";
87     Tree.postorder(T);
88     cout<<endl;
89     return 0;
90 }