二叉树的构造与遍历—先根构造，一维数组存储按层构造，先根，中根，后根遍历输出

最新推荐文章于 2021-05-12 07:34:30 发布

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本文介绍了一种使用模板类实现二叉树的方法，包括通过先序输入创建二叉树、层序输入创建二叉树及先序、中序、后序遍历输出。通过具体的示例代码展示了如何构建和遍历二叉树结构。

// bTreeNode.h #include <iostream> template <class Type> class bTree; template <class Type> class bTreeNode { friend class bTree<Type>; // this template class is not a common used template class // it is used only in template class bTree private: bTreeNode(): data(Type()), lchild(NULL), rchild(NULL) { } Type data; bTreeNode* lchild; bTreeNode* rchild; };

// bTree.h #include "bTreeNode.h" template <class Type> class bTree { public: bTree() // constructor for first root input node, { // when left/right child is empty input child node // data '#' root = new bTreeNode<Type>; PreOrderCreate(root); } bTree(Type* q, int n) { root = new bTreeNode<Type>; LeverCreate(root, q, 0, n); } void PrintPreOrder() // print preorder { PreOrder(root); std::cout << std::endl; } void PrintInOrder() // print inorder { InOrder(root); std::cout << std::endl; } void PrintPostOrder() // print postorder { PostOrder(root); std::cout << std::endl; } private: void PreOrderCreate(bTreeNode<Type>* p) // create tree preorder { std::cin >> p->data; if ('#' != p->data) { p->lchild = new bTreeNode<Type>; p->rchild = new bTreeNode<Type>; PreOrderCreate(p->lchild); if ('#' == p->lchild->data) { delete p->lchild; p->lchild = NULL; } PreOrderCreate(p->rchild); if ('#' == p->rchild->data) { delete p->rchild; p->rchild = NULL; } } else { } } void LeverCreate(bTreeNode<Type>* p, Type* q, int i, int n) { if ('#' != q[i] && i < n) { p->data = q[i]; p->lchild = new bTreeNode<Type>; p->rchild = new bTreeNode<Type>; LeverCreate(p->lchild, q, 2 * i + 1, n); if ('/0' == p->lchild->data) { delete p->lchild; p->lchild = NULL; } LeverCreate(p->rchild, q, 2 * i + 2, n); if ('/0' == p->rchild->data) { delete p->rchild; p->rchild = NULL; } } } void PreOrder(bTreeNode<Type>* p) // first root print { if (NULL != p) { std::cout << p->data << " "; PreOrder(p->lchild); PreOrder(p->rchild); } } void InOrder(bTreeNode<Type>* p) // middle root print { if (NULL != p) { InOrder(p->lchild); std::cout << p->data << " "; InOrder(p->rchild); } } void PostOrder(bTreeNode<Type>* p) // post-root print { if (NULL != p) { PostOrder(p->lchild); PostOrder(p->rchild); std::cout << p->data << " "; } } private: bTreeNode<Type>* root; };

// main.cpp #include "bTree.h" int main() { // the below three trees is one tree // '#' means a node has no left/right child // one lever array store. char* cc = "abcdeg###f##h"; bTree<char> a(cc, 13); a.PrintPreOrder(); a.PrintInOrder(); a.PrintPostOrder(); // first root // enter abd##ef###cg#h### bTree<char> b; b.PrintPreOrder(); b.PrintInOrder(); b.PrintPostOrder(); // '#' asc code is equal to 35 // a b d # # e f # # # c g # h # # # // 97 98 100 35 35 101 102 35 35 35 99 103 35 104 35 35 35 bTree<int> c; c.PrintPreOrder(); c.PrintInOrder(); c.PrintPostOrder(); return 0; }