二叉排序树插入的非递归算法，高分！请大家指点异常！

二叉排序树插入的非递归算法，，高分求助！！！请大家指点错误！！！
#include <stdio.h>
#include <stdlib.h>

#define ENDKEY 0

typedef int KeyType;

typedef struct node
{
KeyType key ;
struct node *lchild,*rchild;
}BSTNode, *BSTree;
int InsertBST(BSTree *bst, KeyType K)
{
BSTree q, s;
s=(BSTree)malloc(sizeof(BSTNode));
s->key=K;
s->lchild = NULL;
s->rchild = NULL;
if ( *bst == NULL ) 
{ 
*bst = s; 
return 1; 
}
q = *bst;
while(q)
{ 
if(K==q->key) return 0;
if(K<q->key) q = q->lchild; 
else q = q->rchild;
}
q = s; 

return 1;  
}
void CreateBST(BSTree *bst)

{ 
KeyType key;
*bst=NULL;
scanf("%d", &key);
while (key!=ENDKEY)  
{
InsertBST(bst, key);
scanf("%d", &key);
}
}

void PreOrder(BSTree root) 
{
if (root!=NULL)
{
printf("%d ",root->key);  
PreOrder(root->lchild);  
PreOrder(root->rchild);  
}
}
void main()
{
BSTree T;
printf("建立二叉排序树，请输入序列:\n");
  CreateBST(&T);
printf("先序遍历输出序列为:");
PreOrder(T);
}

[解决办法]
a=5;b=a;然后改b=10,a还是5吧，你的想法应该是用指针BSTree *q才行，代码类似...

C/C++ code

    BSTree *q, s;...    q = bst;    while (*q) {        if (K==(*q)->key)        {            free(s);            return 0;        }        if (K<(*q)->key)            q = &(*q)->lchild;         else            q = &(*q)->rchild;     }    *q = s;