二叉树的遍历

二叉树的前中后序遍历

// 二叉树的遍历.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include 
#include 
using namespace std;
template <typename T>
class BinaryTree {
     
    vector<T> tree;
public:
    BinaryTree(initializer_list<T> a) :tree(a){
     }
    void preorder(size_t index = 0);
    void inorder(size_t index = 0);
    void postorder(size_t index = 0);
};
int main()
{
     
    BinaryTree<char> bt{
      'A','B','C','D',0,'E','F','G','H',0,0,0,'I' };
    bt.preorder(); cout << endl;
    bt.inorder(); cout << endl;
    bt.postorder(); cout << endl;
}


template<typename T>
void BinaryTree<T>::preorder(size_t index)
{
     
    if (index >= tree.size() || tree[index] == 0)return;
    int left = index * 2 + 1, right = index * 2 + 2;
    cout << tree[index] << ' ';
    preorder(left);
    preorder(right);
}

template<typename T>
void BinaryTree<T>::inorder(size_t index)
{
     
    if (index >= tree.size() || tree[index] == 0)return;
    int left = index * 2 + 1, right = index * 2 + 2;
    inorder(left);
    cout << tree[index] << ' ';
    inorder(right);
}

template<typename T>
void BinaryTree<T>::postorder(size_t index)
{
     
    if (index >= tree.size() || tree[index] == 0)return;
    int left = index * 2 + 1, right = index * 2 + 2;
    postorder(left);
    postorder(right);
    cout << tree[index] << ' ';
}