為什么要刪除自己還要判斷父親是否為NULL，自己都還沒被delete掉，難道父親會被先delete掉嗎？void?Node::Nodedelete() { if?(!this->LeftChild) { this->LeftChild->Nodedelete(); } if?(!this->RightChild) { this->RightChild->Nodedelete(); } if?(!this->ParentNode) { if?(this?==?this->ParentNode->LeftChild) { this->ParentNode->LeftChild?=?nullptr; } if?(this?==?this->ParentNode->RightChild) { this->ParentNode->RightChild?=?nullptr; } } delete?this; }