今晚搞清楚了二叉树的建立和先序遍历，不过现在已经是0:32了，该睡觉了，贴上代码，明天补充细节，加油，晚安！

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#include<iostream>
#include <malloc.h>
#include<stdio.h>
@H_404_12@using @H_404_12@namespace std;
@H_404_12@struct node
{
    @H_404_12@int data;
    @H_404_12@struct node* left;
    @H_404_12@struct node* right;
};
@H_404_12@void visit(node* BT);
node* creat();
node* creat(node* &T);
@H_404_12@void preOrder(node*T);
@H_404_12@int main()
{
    node* BT;
    BT=creat();
    preOrder(BT);
    @H_404_12@return 0;
}
@H_404_12@void visit(node* BT)
{
    cout<<BT->data<<' ';
    //cout<<"hi"<<endl;
}
node* creat()
{
    node* T;
    @H_404_12@int num;
    scanf("%d",&num);
    @H_404_12@if(num=='0')
        T=NULL;
    @H_404_12@else
    {
        T = (node*)malloc(@H_404_12@sizeof(node));
        T->data = num;
        //cout<<num;
        T->left = creat();
        T->right = creat();

    }
    @H_404_12@return T;

}
@H_404_12@void preOrder(node*T)
{
    @H_404_12@if(T==NULL)
        @H_404_12@return;
    @H_404_12@else
    {
        visit(T);
        preOrder(T->left);
        preOrder(T->right);     
    } 
}