二叉树的三种遍历

#include <stdio.h>
#include <malloc.h>
 typedef struct tree_node
 {char data;
 struct tree_node *lchild,*rchild;
 }BT_Node;

#define Tree_NodeLen sizeof(BT_Node)
 BT_Node *tree;
 BT_Node *Creat_BTree(BT_Node *t);
 void Visit_Node(BT_Node *tree);
 void Pre_Order(BT_Node *tree);
 void Mid_Order(BT_Node *tree);
 void After_Order(BT_Node *tree);

 int main(void)
 {
 printf("\n please input tree:\n ");
 tree=Creat_BTree(tree);

 if(tree)
 {
     printf("\n Pre_Order:\n");
 Pre_Order(tree);
 printf("\n");

 printf("\n Mid_Order:\n");
 Mid_Order(tree);
 printf("\n");