树的子结构

/*    18 判断树的子结构：*/bool DoseTree1HasTree2(BinTree* root1, BinTree* root2){    if (root2 == NULL)        return true;    if (root1 == NULL)        return false;    if (root1->m_nValue != root2->m_nValue)        return false;    return DoseTree1HasTree2(root1->m_pLeft, root2->m_pLeft) && DoseTree1HasTree2(root1->m_pRight, root2->m_pRight);}bool HasSubTree(BinTree* root1, BinTree* root2){    bool res = false;    if (root1 != NULL && root2 != NULL)    {        if (root1->m_nValue == root2->m_nValue)            res = DoseTree1HasTree2(root1, root2);        if (!res)            HasSubTree(root1->m_pLeft, root2);        if (!res)            HasSubTree(root1->m_pRight, root2);    }    return res;}