实现函数：

int count=0;
int LeafNode(BiTree T){
	if(T==NULL) return 0;
	else if(T->lchild==NULL&&T->rchild==NULL) count++;//是否是叶子结点的判断
	LeafNode(T->lchild);
	LeafNode(T->rchild);
	return chount;
}