数据结构 - 互换二叉树中所有结点的左右子树（C++）

#include <iostream>#define NULL 0using namespace std;template<class T>struct BTNode{T data;BTNode<T> *lChild, *rChild;BTNode();BTNode(const T &val, BTNode<T> *Childl = NULL, BTNode<T> *Childr = NULL){data = val;lChild = Childl;rChild = Childr;}BTNode<T>* CopyTree(){BTNode<T> *l, *r, *n;if(&data == NULL){return NULL;}l = lChild->CopyTree();r = rChild->CopyTree();n = new BTNode<T>(data, l, r);return n;}};template<class T>BTNode<T>::BTNode(){lChild = rChild = NULL;}template<class T>class BinaryTree{public:BTNode<T> *root;BinaryTree();~BinaryTree();void Pre_Order();void In_Order();void Post_Order();void DestroyTree();BTNode<T>* MakeTree(const T &element, BTNode<T> *l, BTNode<T> *r){root = new BTNode<T> (element, l, r);if(root == NULL){cout << "Failure for applying storage address, system will close the process." << endl;exit(1);}return root;}private:void PreOrder(BTNode<T> *r);void InOrder(BTNode<T> *r);void PostOrder(BTNode<T> *r);void Destroy(BTNode<T> *&r);};template<class T>BinaryTree<T>::BinaryTree(){root = NULL;}template<class T>BinaryTree<T>::~BinaryTree(){DestroyTree();}template<class T>void BinaryTree<T>::Pre_Order(){PreOrder(root);}template<class T>void BinaryTree<T>::In_Order(){InOrder(root);}template<class T>void BinaryTree<T>::Post_Order(){PostOrder(root);}template<class T>void BinaryTree<T>::DestroyTree(){Destroy(root);}template<class T>void BinaryTree<T>::PreOrder(BTNode<T> *r){if(r != NULL){cout << r->data << ' ';PreOrder(r->lChild);PreOrder(r->rChild);}}template<class T>void BinaryTree<T>::InOrder(BTNode<T> *r){if(r != NULL){InOrder(r->lChild);cout << r->data << ' ';InOrder(r->rChild);}}template<class T>void BinaryTree<T>::PostOrder(BTNode<T> *r){if(r != NULL){PostOrder(r->lChild);PostOrder(r->rChild);cout << r->data << ' ';}}template<class T>void BinaryTree<T>::Destroy(BTNode<T> *&r){if(r != NULL){Destroy(r->lChild);Destroy(r->rChild);delete r;r = NULL;}}template<class T>void Swap(BTNode<T> *r) // Swap left, right subtree of all nodes.{BTNode<T> *p;if(r){p = r->lChild;r->lChild = r->rChild;r->rChild = p; // Swap left, right child.Swap(r->lChild); // Swap left, right subtree of all the nodes in left subtree.Swap(r->rChild); // Swap left, right subtree of all the nodes in right subtree.}}void main(){BTNode<char> *b, *c, *d, *e, *f, *g;BinaryTree<char> a;b = a.MakeTree('F', NULL, NULL);c = a.MakeTree('E', NULL, NULL);d = a.MakeTree('D', NULL, NULL);e = a.MakeTree('C', b, NULL);f = a.MakeTree('B', d, c);g = a.MakeTree('A', f, e);cout << "Pre Order: ";a.Pre_Order();cout << endl;cout << "In Order: ";a.In_Order();cout << endl;cout << "Post Order: ";a.Post_Order();cout << endl;cout << endl << "------Swap left, right subtree of all nodes------" << endl << endl;Swap(a.root);cout << "Pre Order: ";a.Pre_Order();cout << endl;cout << "In Order: ";a.In_Order();cout << endl;cout << "Post Order: ";a.Post_Order();cout << endl << endl;}// Output:/*Pre Order: A B D E C FIn Order: D B E A F CPost Order: D E B F C A------Swap left, right subtree of all nodes------Pre Order: A C F B E DIn Order: C F A E B DPost Order: F C E D B A*/