void locate(BitTree t, int x)//在二叉树t中查找值为x的结点
{
BitTree p;
p=t;
if (t == NULL)printf("0\n");
else if( t->data == x)printf("%d\n",p->data);
else
{ p=t->lchild;
if (p)locate(t->lchild, x);
else
locate(t->rchild, x);
}
}