# include 
# define maxnum 100 
using namespace std; 

Typedef struct BTNode {
Char data; 
Struct BTNode * lchild; 
Struct BTNode * rchild; 
} BTNode; 
Void visite (BTNode * P) 
{
Cout & lt; 
} 
//before sequence traversal 
Void preorder (BTNode * P) 
{
If (P!=NULL) 
{
Visite (P); 
Preorder (P - & gt; Lchild); 
Preorder (P - & gt; Rchild); 
} 
} 
//in the sequence traversal 
Void inorder (BTNode * P) 
{
If (P!=NULL) 
{
Inorder (P - & gt; Lchild); 
Visite (P); 
Inorder (P - & gt; Rchild); 
} 
} 
//after sequence traversal 
Void postorder (BTNode * P) 
{
If (P!=NULL) 
{
Postorder (P - & gt; Lchild); 
Postorder (P - & gt; Rchild); 
Visite (P); 
} 
} 
//level traversal 
Void level (BTNode * p) 
{
Int the front and rear; 
Que BTNode * [maxnum]; 
The front rear of==0; 
BTNode * q; 
If (p!=NULL) 
{
Rear=(rear + 1) % maxnum; 
Que [rear]=p; 
While (front!=rear) 
{
The front=(front + 1) % maxnum; 
Q=que (front), 
Visite (q); 
If (q - & gt; Lchild!=NULL) 
{
Rear=(rear + 1) % maxnum; 
Que (rear)=q - & gt; Lchild; 
} 
If (p - & gt; Rchild!=NULL) 
{
Rear=(rear + 1) % maxnum; 
Que (rear)=q - & gt; Rchild; 
} 
} 
} 
} 
Int main () 
{
BTNode * node1=new BTNode; 
BTNode * 2=new BTNode; 
BTNode * node3=new BTNode; 
BTNode * node4=new BTNode; 
BTNode * node5=new BTNode; 
Node1 - & gt; Data='https://bbs.csdn.net/topics/A'. 
Node1 - & gt; Lchild=2; 
Node1 - & gt; Rchild=node3; 
2 - & gt; Data='https://bbs.csdn.net/topics/B'. 
2 - & gt; Lchild=NULL; 
2 - & gt; Rchild=NULL; 
Node3 - & gt; Data='https://bbs.csdn.net/topics/C'. 
Node3 - & gt; Lchild=node4; 
Node3 - & gt; Rchild=node5; 
Node4 - & gt; Data='https://bbs.csdn.net/topics/E'. 
Node4 - & gt; Rchild=NULL; 
Node4 - & gt; Lchild=NULL; 
Node5 - & gt; Data='https://bbs.csdn.net/topics/D'. 
Node5 - & gt; Lchild=NULL; 
Node5 - & gt; Rchild=NULL; 
Cout & lt; <"Big stick, please enter the order you want to choose the binary sort tree" & lt; Cout & lt; <"1: sort order 2: first ranking order 3: after the sort order 4: level traversal" & lt; Int gengzi; 
Cin & gt;> Gengzi; 
The switch (gengzi) 
{
Case 1: 
Cout & lt; <"Big stick the preorder traversal for you choose:"; 
Preorder (node1); 
break; 
Case 2: 
Cout & lt; <"Big stick in your choice of sequence traversal is:"; 
Inorder (node1); 
break; 
Case 3: 
Cout & lt; <"Big stick in your choice of sequence traversal is:"; 
Postorder (node1); 
break; 
Case 4: 
Cout & lt; <"Big root level traversal for you choose:"; 
Level (node1); 
break; 
Default: 
Cout & lt; <"Big root by what ah you in disorderly!!! "; 
} 
}