二叉树的构建出问题，不知道错在哪里

Question

我也不知道是哪里有问题，，求助
代码
#include
using namespace std;

typedef struct BTNode
{
int data;
BTNode*LChild,*RChild;
}BTNode,BTRoot;

BTNode*MakeTreeNode(int x)
{
BTNode*ptr;
ptr->data=x;
ptr->LChild=NULL;
ptr->RChild=NULL;
return ptr;
}

void MakeTree(BTNode*root,BTNode*left,BTNode*right)
{
root->LChild=left;
root->RChild=right;
}

void Traverse(BTNode*BT)
{
if(BT)
{
cout<data;
Traverse(BT->LChild);
Traverse(BT->RChild);
}
}

int main()
{
BTNode *p1=MakeTreeNode(1);
BTNode *p2=MakeTreeNode(2);
BTNode *p3=MakeTreeNode(3);
BTNode *p4=MakeTreeNode(4);
BTNode *p5=MakeTreeNode(5);
BTNode *p6=MakeTreeNode(6);
BTNode *p7=MakeTreeNode(7);
BTNode*BT;
MakeTree(p1,p2,p3);
MakeTree(p2,p4,p5);
MakeTree(p3,p6,p7);
BT=p1;

Traverse(BT);

cout<<p1->data;//每个结点的数值都是7
cout<<p2->data;
cout<<p3->data;
return 0;

}

Answer 1

觉得程序跑不起来吧，MakeTreeNode函数中的ptr需要你用new或者malloc申请内存的