#include <stdlib.h>
#include <iostream>
#include<sstream>
using namespace std;
typedef struct node *Nodeptr;
typedef struct node {
int val; 
Nodeptr left; 
Nodeptr right; 
} Node; 

Node *addtree(Node *tree, double val);
void preorder(Node *tree);
Node *talloc(void);
void inorder(Node *tree);
void postorder(Node *tree);

int main() {

string s;
while (getline(cin,s) ){ 
stringstream ss;
ss<<s;
Node *root = NULL;
double n;
while(ss>>n){
root = addtree(root, n);
}


string d;
cin>>d;
if(d=="pre"){
preorder(root);
}
if(d=="in"){
inorder(root);
}
if(d=="post"){
postorder(root);
}
cout << endl;
}
return 0;
}

Node *addtree(Node *tree, double val) { 
if (tree == NULL) { 
tree = talloc(); 
tree->val = val; 
tree->left = NULL; 
tree->right = NULL;
} else if (val < tree->val) 
tree->left = addtree(tree->left, val);
else
tree->right = addtree(tree->right, val);
return tree; 
}

void preorder(Node *tree) { 

cout<<tree->val<<' '; 
if(tree->left)preorder(tree->left); 
if(tree->right)preorder(tree->right); 
}
void inorder(Node *tree){

if(tree->left)inorder(tree->left);
cout<<tree->val<<' ';
if(tree->right)inorder(tree->right);
}
void postorder(Node *tree){

if(tree->left) preorder(tree->left);
if(tree->right)preorder(tree->right);
cout<<tree->val<<' ';
}

Node *talloc(void) { 
return (Node *) malloc(sizeof(struct node)); 
}

以上NA40%，請大神幫幫我

不用了，謝謝